"If you have the ambition and quality, we count on you and give you the chance to develop. With development, there is also performance. That's why it's a great story for Florian but also for us as a club," Simon Rolfes told Stats Perform.

Bayer Leverkusen had money to splash after Chelsea paid a club-record fee to prise German star Kai Havertz from BayArena at the start of 2020-21. His absence was supposed to leave a glaring hole in North Rhine-Westphalia and prompt a frantic search in the transfer market.

But sporting director Rolfes and Leverkusen had other ideas. Rather than use the money recouped in the blockbuster Havertz transfer, Die Werkself opted to look in their own backyard for a replacement – 18-year-old teenage sensation Florian Wirtz.

Leverkusen's faith in youth and their clearly defined philosophy has served them well previously, and they're being rewarded once again by the club's latest wonderkid, who has put Havertz well and truly in the rear-view mirror as Europe's elite queue for his signature.

At home in the number 10 role behind a striker or even as a deep-lying playmaker, Wirtz can do it all on the pitch – as next opponents Bayern Munich may find out on Sunday.

Leverkusen prised Wirtz from Cologne in 2020. Dubbed "the best midfielder to come through the club in 30 years" by local newspaper Kolner Express, Bayern, Borussia Dortmund, RB Leipzig and Liverpool were all circling after Wirtz captained boyhood team Cologne to Under-17 German Championship glory in 2019, but Leverkusen eventually won the race.

Rolfes had first watched Wirtz at the age of 13. He was immediately mesmerised by the Brauweiler-born sensation, who has firmly established himself in the Leverkusen XI, quickly becoming the new face of Die Werkself.

From his junior days, Wirtz has been great at exploiting gaps and creating space in midfield while churning out goalscoring chances with his devastating awareness. Not to mention his defence-splitting passing ability. Five years on and nothing has changed on the international stage.

"Extraordinary player," Rolfes told Stats Perform prior to the international break, after which Leverkusen now prepare to face champions Bayern in a top-of-the-table Bundesliga clash. "I saw him the first time when he was 13 and followed him all the time. Spoke with him before he moved to us, with the parents a lot of times and tried to convince them that it was the right step to come to us and accelerate his development. I and the whole club are very happy that he is with us. That's the interesting thing, I watched him the first time at 13 and he is still playing the same. 14,15, 16, always in that kind of style."

When a player breaks a record held by Havertz at Leverkusen, it is a sign to sit up and take notice.

Wirtz was swiftly thrust into the first team, becoming Leverkusen's youngest-ever debutant at the age of 17 years and 16 days, eclipsing Havertz's record, in last season's 4-1 rout of Werder Bremen in 2019-20. After a handful of appearances in the coronavirus-hit campaign, Wirtz played 29 Bundesliga games, which yielded five goals and as many assists in the post-Havertz era in 2020-21. In February 2021, Wirtz became the first player in the league's history to score five goals before celebrating his 18th birthday.

So, when it comes to comparing Wirtz to Havertz through their first 42 Bundesliga appearances with Leverkusen, how do they stack up against each other?

Wirtz has an equal split between goals and assists (10 each), averaging his 20 goal involvements once every 148 minutes across his top-flight career so far. That's quicker than Havertz managed at the same stage of his Bundesliga career, with his 16 goal involvements in his first 42 apps coming at an average of 165 minutes.

Wirtz also proved a shade more productive in front of goal, with an expected goals per 90 average of 0.16 compared to Havertz's 0.14, but the now-Chelsea forward was able to get more involved in the average game with 65 touches per 90 compared to Wirtz's 58 per 90.

"I wouldn't say they're similar. They're for sure similar in terms of extraordinary qualities and potential for really big careers," Rolfes said. "I would say at the end, Kai plays a little bit more forward and is very good in going deep with a lot of speed. Sometimes it doesn’t look like it because he is so tall but he is incredibly fast. Very direct, fantastic shot with his left foot and a good header. With his height, a very good header of the ball.

"With Florian, I think from a positional sense he is a little bit deeper. More technique in small spaces I would say. Kai likes to use his speed. They are quite different. They unfortunately only played/trained half a year together. It would be nice to have them both together in the squad at the moment because one right foot, one left. They would fit very good together."

With so much attention from a very young age, it is easy for some players to get swept up amid the hype and interest. Not Wirtz.

Wirtz has continued to shatter records and dazzle in the Bundesliga. Against Mainz on matchday six of this season, the Germany international became the youngest player to score 10 goals in Germany’s top-flight, doing so 208 days younger than Lukas Podolski (18 years, 353 days for Cologne in 2004).

No player in the Bundesliga this season has more assists than Wirtz (five) through seven rounds.

With four league goals in just six appearances, he is already only one goal shy of matching last season's haul, despite an expected goals (xG) goal value of 1.0 – no other player has such a large difference between his goals and expected goals.

His nine goal involvements in this season's Bundesliga are only surpassed by Dortmund star Erling Haaland (10), while Wirtz has the best shot conversion rate (36.4 per cent) among all players with at least three goals in 2021-22.

As Wirtz goes from prospect to genuine star, it all comes down to his mindset.

"The attitude is very good. With players and we could see it with Kai Havertz, they know their quality. They are 18 and self-confident because they know about their quality. Special players have that – they can feel that, feel it directly on the pitch. Playing with other good players, they're able to handle it and adapt to the different speed of the game," said Rolfes.

"In that case, they are quite far [developed] and they know there's interest in them because also with 14, 15, 16 it's normal big clubs watched him play. With Florian and Kai, it's quite the same. They always know they’re interesting and extraordinary players."

In all competitions in 2021-22, Wirtz (11) is the only player in Europe's big-five leagues 18 or younger to be involved in seven or more goals, having already found the back of the net twice in the Europa League.

Wirtz has been involved in a goal across all competitions every 47 minutes so far this term – at least up until the international break, it was the best rate of all players in Europe's top five leagues with at least 500 minutes, ahead of Haaland (51 mins), Real Madrid's Karim Benzema (52 mins), Bayern talisman Robert Lewandowski (60 mins) and Liverpool star Mohamed Salah (65 mins).

"In the youth teams, the difference in the quality between him and others was much higher. The game in the youth is around them. Now, he also has a big influence on the game, but he has to position himself better to get the ball and use his quality. Players with extraordinary quality have the ability to find the right spaces but in professional teams they have to wait a little bit in their position and then use their quality," former Leverkusen midfielder Rolfes said. "Compared to the youth where they are doing everything."

It's a frightening thought when you remember Wirtz only celebrated his 18th birthday in May and consider how much growth there is to come from Leverkusen’s prized asset.

Despite being so young, Wirtz is already important in Leverkusen's attacking production – he's been involved in 26 open-play attacking sequences in the Bundesliga this season, with only two players at the club involved in more. Of those 26, 12 have come as the creator of the chance, which is more than any Leverkusen team-mate.

"He will improve year by year. Although he already has a high level. His biggest strength and you could see that in all the years in the youth team, is that he gives his best in each game," added Rolfes. "Doesn't matter where he was playing or which team-mates he was playing with. The first team, U19, U13 etc, he was always giving his best. That is a key element in his development that he is able to adapt at higher levels but he has ambition to always improve and you have to improve.

"Sometimes improvement is also a little bit about changing your game. For sure the opponents want to defend him and watch him, so improvement is sometimes changing a little bit. I'm totally convinced he will have a great career because he has the right mindset to develop. If he keeps that, he is 18 and young, it's a really young guy and he has strengthen his personality etc – that’s normal. We all know how we've been at 18 but if he keeps his mindset and development, he will have a fantastic career."

Bayer Leverkusen wonderkid Florian Wirtz has been named as September's Bundesliga Player of the Month after a series of outstanding performances.

The 18-year-old scored three goals and registered two assists in three league games last month, helping Leverkusen to second in the table - behind Bayern Munich only on goal difference.

Wirtz has already managed four goals and leads the Bundesliga charts for assist (five) in just six appearances. In total, the versatile attacker has been involved in a goal every 47 minutes across all competitions, the best minutes per goal involvement ratio of all players in Europe's top five leagues to play at least 500 minutes.

The attacking midfielder's winner against Mainz also made him the youngest player to reach double figures for goals in the German top-flight, doing so at 208 days younger than Lukas Podolski (18 years, 353 days for Cologne in 2004).

Leverkusen sporting director and former midfielder Simon Rolfes praised the teenager's talent and willingness to better himself, comparing him to Kai Havertz, who was sold to Chelsea in 2020 after a similarly meteoric rise.

"The attitude is very good," Rolfes said to Stats Perform. "With players and we could see it with Kai Havertz, they know their quality. They are 18 and self-confident because they know about their quality.

"Special players have that – they can feel that, feel it directly on the pitch. Playing with other good players, they're able to handle it and adapt to the different speed of the game.

"He will improve year by year. Although he already has a high level. His biggest strength and you could see that in all the years in the youth team, is that he gives his best in each game.

"Doesn't matter where he was playing or which team-mates he was playing with. The first team, U19, U13 etc, he was always giving his best. That is a key element in his development that he is able to adapt at higher levels but he has the ambition to always improve and you have to improve."

Leverkusen captain and first-choice goalkeeper Lukas Hradecky, 31, echoed Rolfes' sentiments as he hailed the work of the youngster following his individual accolade.

"Florian is a great player," Hradecky said to the Bundesliga's official website. "He’s doing an outstanding job and works hard on himself."

Wirtz will be hoping to maintain his streak of scoring or assisting in every Bundesliga appearance so far this season as Leverkusen host league leaders Bayern on October 17.

"If you have the ambition and quality, we count on you and give you the chance to develop. With development, there is also performance. That's why it's a great story for Florian but also for us as a club," Simon Rolfes told Stats Perform.

Bayer Leverkusen had money to splash after Chelsea paid a club-record fee to prise German star Kai Havertz from BayArena at the start of 2020-21. His absence was supposed to leave a glaring hole in North Rhine-Westphalia and prompt a frantic search in the transfer market.

But sporting director Rolfes and Leverkusen had other ideas. Rather than use the money recouped in the blockbuster Havertz transfer, Die Werkself opted to look in their own backyard for a replacement – 18-year-old teenage sensation Florian Wirtz.

Leverkusen's faith in youth and their clearly defined philosophy has served them well previously, and they're being rewarded once again by the club's latest wonderkid, who has put Havertz well and truly in the rear-view mirror as Europe's elite queue for his signature.

At home in the number 10 role behind a striker or even as a deep-lying playmaker, Wirtz can do it all on the pitch.

Leverkusen prised Wirtz from Cologne in 2020. Dubbed "the best midfielder to come through the club in 30 years" by local newspaper Kolner Express, Bayern Munich, Borussia Dortmund, RB Leipzig and Liverpool were all circling after Wirtz captained boyhood team Cologne to Under-17 German Championship glory in 2019, but Leverkusen eventually won the race.

Rolfes had first watched Wirtz at the age of 13. He was immediately mesmerised by the Brauweiler-born sensation, who has firmly established himself in the Leverkusen XI, quickly becoming the new face of Die Werkself.

From his junior days, Wirtz has been great at exploiting gaps and creating space in midfield while churning out goalscoring chances with his devastating awareness. Not to mention his defence-splitting passing ability. Five years on and nothing has changed on the international stage.

"Extraordinary player," Rolfes told Stats Perform. "I saw him the first time when he was 13 and followed him all the time. Spoke with him before he moved to us, with the parents a lot of times and tried to convince them that it was the right step to come to us and accelerate his development. I and the whole club are very happy that he is with us. That's the interesting thing, I watched him the first time at 13 and he is still playing the same. 14,15, 16, always in that kind of style."

When a player breaks a record held by Kai at Leverkusen, it is a sign to stand up and take notice.

Wirtz was swiftly thrust into the first team, becoming Leverkusen's youngest-ever debutant at the age of 17 years and 16 days, eclipsing Havertz's record, in last season's 4-1 rout of Werder Bremen in 2019-20. After a handful of appearances in the coronavirus-hit campaign, Wirtz played 29 Bundesliga games, which yielded five goals and as many assists in the post-Havertz era in 2020-21. In February 2021, Wirtz became the first player in the league's history to score five goals before celebrating his 18th birthday.

So, when it comes to comparing Wirtz to Havertz through their first 42 Bundesliga appearances with Leverkusen, how do they stack up against each other?

Wirtz has an equal split between goals and assists (10 each), averaging his 20 goal involvements once every 148 minutes across his top-flight career so far. That's quicker than Havertz managed at the same stage of his Bundesliga career, with his 16 goal involvements in his first 42 apps coming at an average of 165 minutes.

Wirtz also proved a shade more productive in front of goal, with an expected goals per 90 average of 0.16 compared to Havertz's 0.14, but the now-Chelsea forward was able to get more involved in the average game with 65 touches per 90 compared to Wirtz's 58 per 90.

"I wouldn't say they're similar. They're for sure similar in terms of extraordinary qualities and potential for really big careers," Rolfes said. "I would say at the end, Kai plays a little bit more forward and is very good in going deep with a lot of speed. Sometimes it doesn’t look like it because he is so tall but he is incredibly fast. Very direct, fantastic shot with his left foot and a good header. With his height, a very good header of the ball.

"With Florian, I think from a positional sense he is a little bit deeper. More technique in small spaces I would say. Kai likes to use his speed. They are quite different. They unfortunately only played/trained half a year together. It would be nice to have them both together in the squad at the moment because one right foot, one left. They would fit very good together."

With so much attention from a very young age, it is easy for some players to get swept up amid the hype and interest. Not Wirtz.

Wirtz has continue to shatter records and dazzle in the Bundesliga. Against Mainz on matchday six of this season, the Germany international became the youngest player to score 10 goals in Germany’s top-flight, doing so 208 days younger than Lukas Podolski (18 years, 353 days for Cologne in 2004).

No player in the Bundesliga this season has more assists than Wirtz (five) through seven rounds.

With four league goals in just six appearances, he is already only one goal shy of matching last season's haul, despite an expected goals (xG) goal value of 1.0 – no other player has such a large difference between his goals and expected goals.

His nine goal involvements in this season's Bundesliga are only surpassed by Dortmund star Erling Haaland (10), while Wirtz has the best shot conversion rate (36.4 per cent) among all players with at least three goals in 2021-22.

As Wirtz goes from prospect to genuine star, it all comes down to his mindset.

"The attitude is very good. With players and we could see it with Kai Havertz, they know their quality. They are 18 and self-confident because they know about their quality. Special players have that – they can feel that, feel it directly on the pitch. Playing with other good players, they're able to handle it and adapt to the different speed of the game," said Rolfes.

"In that case, they are quite far [developed] and they know there's interest in them because also with 14, 15, 16 it's normal big clubs watched him play. With Florian and Kai, it's quite the same. They always know they’re interesting and extraordinary players."

In all competitions in 2021-22, Wirtz (11) is the only player in Europe's big-five leagues 18 or younger to be involved in seven or more goals, having already found the back of the net twice in the Europa League.

Wirtz has been involved in a goal across all competitions every 47 minutes so far this term – it is the best ratio of minutes per goal involvement of all players in Europe's top-five leagues with at least 500 minutes, ahead of Haaland (51 mins), Real Madrid's Karim Benzema (52 mins), Bayern talisman Robert Lewandowski (60 mins) and Liverpool star Mohamed Salah (65 mins).

"In the youth teams, the difference in the quality between him and others was much higher. The game in the youth is around them. Now, he also has a big influence on the game, but he has to position himself better to get the ball and use his quality. Players with extraordinary quality have the ability to find the right spaces but in professional teams they have to wait a little bit in their position and then use their quality," former Leverkusen midfielder Rolfes said. "Compared to the youth where they are doing everything."

It's a frightening thought when you remember Wirtz only celebrated his 18th birthday in May and how much growth there is to come from Leverkusen’s prized asset.

Despite being so young, Wirtz is already important in Leverkusen's attacking production – he's been involved in 26 open-play attacking sequences in the Bundesliga this season, with only two players at the club involved in more. Of those 26, 12 have come as the creator of the chance, which is more than any Leverkusen team-mate.

"He will improve year by year. Although he already has a high level. His biggest strength and you could see that in all the years in the youth team, is that he gives his best in each game," added Rolfes. "Doesn't matter where he was playing or which team-mates he was playing with. The first team, U19, U13 etc, he was always giving his best. That is a key element in his development that he is able to adapt at higher levels but he has ambition to always improve and you have to improve.

"Sometimes improvement is also a little bit about changing your game. For sure the opponents want to defend him and watch him, so improvement is sometimes changing a little bit. I'm totally convinced he will have a great career because he has the right mindset to develop. If he keeps that, he is 18 and young, it's a really young guy and he has strengthen his personality etc – that’s normal. We all know how we've been at 18 but if he keeps his mindset and development, he will have a fantastic career."

After another busy off-season at Bayer Leverkusen, many would have tipped a slow start with a new face in the dugout.

With Peter Bosz relieved of his duties, Simon Rolfes and Leverkusen turned to Gerardo Seoane on the back of three consecutive Swiss Super League titles at the helm of Young Boys.

Star winger Leon Bailey also headlined the departures at BayArena, a year on from Kai Havertz's big-money move to Chelsea. Factor in major international tournaments prior to the 2021-22 campaign – Euro 2020, the Copa America and the Olympic Games – and it made for a challenging pre-season.

But Leverkusen have hit the ground running in the Bundesliga – a 4-0 rout of Borussia Monchengladbach and wins over Augsburg (4-1), Stuttgart (3-1) and Mainz (1-0) helping Die Werkself to second place through six games, three points behind leaders and champions Bayern Munich.

Leverkusen sporting director Rolfes told Stats Perform: "We're happy with the start of the season because it was a difficult summer for us but also the other teams who have a lot of international players. This summer with the Copa America, Euros, Olympic Games... there were a lot of players from us involved. A player from us won the Copa America and Olympics, so only the Euros we missed.

"That's why the pre-season was really difficult. The players step in, week by week, and I think one week before the start of the season, we had our final squad together. The transfer market due to coronavirus was also very different and late. That's why I'm very happy. We had good opponents."

"We were not happy with the last season," said Rolfes, whose Leverkusen finished sixth in 2020-21 while losing in the DFB-Pokal last 16 and Europa League round of 32. "A very good start but the end was difficult. We reached international competition okay, but we are ambitious and want more this season. You can imagine the Champions League is a big goal but also the DFB-Pokal and Europa League to go further.

"What's very important for our club is development. One thing is performance and also the result at the end of the season, but development is very important. Develop the players, make them better. Then we have the chance to also perform today in the best way. We have a lot of young players – we want to develop them to their best level. That's also good for the performance today."

Seoane's 13 points after six Bundesliga matches represent the best record of any Leverkusen head coach since Sami Hyypia (15) in 2013. For the North Rhine-Westphalia outfit, it is their best start to a top-flight season since 2019-20 (also 13), while they have only scored more goals after six matches in 2008-09 (18) than in the current campaign (16).

Leverkusen have exceeded their expected goals (xG) tally by almost eight goals this Bundesliga campaign – 7.7 (16 goals at 8.3 xG), a league best.

"One important point is football knowledge," Rolfes replied when asked what attracted Leverkusen to 42-year-old Swiss coach Seoane. "Also the leadership, that's very interesting. The leadership of the group as a head coach is very important. If you're in training, the assistant coaches can do things. If you don't feel so comfortable or don't have so many qualities, you can find the right team.

"The leadership as a head coach, you must have. That's a big strength, besides the football knowledge he has. He speaks six different languages – very good for an international squad to speak with the players in their language. That helps a lot to get the right connection to take them on their way and development."

Under Seoane, Leverkusen play a more patient brand of football, allowing their opposition more time on the ball in the Bundesliga rather than consistently pressing high up the field.

Through the first six games last season, Leverkusen allowed 11.1 passes per defensive action, compared to 12.2 with Seoane in charge, as Leverkusen look to instead create counter-attacks from deeper positions – their averaging starting distance at 38.6 metres from their own goal, compared to 42.2m previously. Their 17 direct attacks this term dwarf last year's six at the same stage.

Leverkusen recorded 8.7 high turnovers per match through six rounds last season, compared to 5.3 this time around, but they have scored four goals from such situations already in the Bundesliga – at least twice as many as any other side and more than any other team in Europe's top five leagues in 2021-22. They actually had fewer goals (three) from high turnovers after six games last time out, proving more ruthless this term.

Still, Leverkusen's philosophy remains the same, despite a new coach and altered approach, and it will continue to be the case with Seoane and beyond under Rolfes.

"We choose players, signing as a club," Rolfes said as he discussed the need to adopt a clear vision, instead of changing philosophy with every coach. "We sign the players for a specific style to get the most out of the squad, the player and to develop them in the best way. If you play in the totally other direction than you want to develop the players, you will not succeed. That's important to have a clear vision as a club. How you want to play and then choose the right coach in the best case.

"Every head coach of a pro team has their specific style. That's not the problem, but the main direction has to be clear. That's my task at the end to choose the right coach for the main direction. And then, the individual approach or quality of the coach, it's important you get something fresh in the club, team. The main direction is important and the club has to define the vision."

Leverkusen are one of Germany's biggest clubs, but not since the 1993 DFB-Pokal have they celebrated silverware.

They have come close on numerous occasions in the Bundesliga – runners-up in 1996-97, 1998-99, 1999-2000, 2001-02 and 2010-11 – while they also reached the 2001-02 Champions League final, succumbing to Real Madrid and Zinedine Zidane's iconic volley in Glasgow. There were Pokal final appearances in 2001-02, 2008-09 and 2019-20, too.

But an exciting and entertaining Leverkusen, even in the post-Havertz era, are on the right track amid Bayern's domestic and European dominance.

And that is thanks to teenage sensation Florian Wirtz.

The 18-year-old prodigy has continued to shine, filling the huge void left by countryman Havertz, amid rave reviews from across Europe.

Wirtz, who was prised from boyhood club Cologne last year, is the youngest player in Bundesliga history to reach 10 goals.

Leverkusen's Wirtz has already been directly involved in eight Bundesliga goals (four goals, four assists) in 292 minutes across the first six matchdays in 2021-22. Only Borussia Dortmund star Erling Haaland has had more direct goal involvements this term than the teenager.

Since Opta's detailed data collection began in 2004-05, only Patrick Helmes in 2008-09 and Stefan Kiessling in 2013-14 had previously registered as many direct goal involvements for Leverkusen after the first six matches to a Bundesliga season

Setting the standard across Europe, the new face of Leverkusen averages 37 minutes per goal involvement, which ranks best among players in the top five leagues (minimum 100 minutes played), ahead of Madrid superstar Karim Benzema (41 minutes). The 34-year-old Frenchman is the only one of those players to have exceeded his xG by a larger margin (4.8) than Wirtz (3.2) this season.

Already capped three times at international level, Wirtz has scored in four straight games, including Leverkusen's Europa League win against Ferencvaros on matchday one.

As Wirtz soars to new heights, Leverkusen are reaping the rewards of a unified philosophy and their faith in the midfielder.

"I think it's a real good example of how the club is working and how the club is thinking," Rolfes, who made almost 400 appearances for Leverkusen between 2005 and 2015, said. "The situation with Kai and Florian. Florian was here or came in the winter [of 2020] and made eight appearances after the lockdown with the first team. Then at the end of the [2019-20] season, Kai went to Chelsea.

"For sure, we got a lot of money for Kai, but we decided to focus on Florian Wirtz for the number 10 position. We don't sign any player as a replacement for Kai. For sure, we had some money to spend on an experienced player in the number 10 position, but we didn't do that. We said okay, the young guy will be the future and has the potential to replace or play very good in that position. We have him already in the club, so we trust him and try to develop him. That's why we sign players in other positions, where we needed improvement.

"That was a big sign for the player and for the chance you have as a young player in Leverkusen. If you have the ambition and quality, we count on you and give you the chance to develop. With development, there is also performance. That's why it's a great story for Florian but also for us as a club."

Wirtz's exploits have not gone unnoticed, however, with Bayern reportedly trying to sign the Germany international, while the likes of Manchester United, Liverpool, Chelsea and Arsenal have also been linked.

But Leverkusen have no plans to sell as Rolfes – who first watched Wirtz as a 13-year-old – added: "He has a long contract until 2026. We do not have to sell players early. We want to develop him, develop our team and club with him.

"So, there are rumours, okay. You cannot avoid that, but it's not our goal to sell him. The players at one time or point in their career make the next step to world-class level, that's okay for us, but not too early. He is a really young player. That was also with Kai – he was also extraordinary and some years with us and then maybe there's the next step. But not too early.

In February, Leverkusen extended their partnership with Stats Perform for the use of Edge Analysis – the most sophisticated football match preparation tool available.

Powered by tracking and event data, Edge Analysis applies unique AI models to unlock objective, dynamic and predictive insights to enhance pre and post-match analysis processes, delivering unique performance insights on all upcoming opponents. The platform uses over 100 AI-driven KPIs to deliver eight unique patented AI models, delivering objective insights within seconds, all linked to video.

"Data/sport technology is very important for us because I think there's huge potential in the future," Rolfes said of the deal. "Data will be better and better because the cameras/GPS tracking provides more precise data.

"We have now not only data in the computer and no one has the time to analyse it, we have the tools with AI, and find the right KPIs for you. That's very important for the match preparation and for the scouting process to be fast, really precise. That's why we invest in that topic here. That's through partnership and investing in our staff to get knowledge, to develop because, at the moment, we are only at the beginning. That's why you have to invest, to be a pioneer or leader in that topic."

Kai Havertz has all the qualities to be "world class" but was always likely to need time to settle in at Chelsea, according to Bayer Leverkusen's sporting director Simon Rolfes.  

The Blues spent a reported £72million (€80m) to bring the Germany international from Leverkusen in September, yet he has so far struggled to justify the hefty price tag.  

The attacking midfielder was one of several big-money signings during a busy close-reason recruitment drive, with compatriot Timo Werner - who arrived from RB Leipzig - also enduring a difficult start to life at Stamford Bridge. 

Havertz has managed five goals and five assists, as well as 23 chances created (1.4 per 90 minutes) and five big chances created (0.3 per 90) in 25 appearances so far in 2020-21.  

For comparison, during his final season at Leverkusen, he registered 18 goals (0.43 per 90), nine assists (0.21 per 90), 84 chances created (1.99 per 90), 20 big chances created (0.47 per 90) from 45 appearances.  

Chelsea's struggles on the pitch this term saw club legend Frank Lampard sacked and replaced by Thomas Tuchel, and Rolfes feels it is unfair to focus purely on Havertz, who he is backing to show his true abilities in the Premier League.

"It's always difficult if you change country and a little bit of a different style. That's the same if we sign players," Rolfes told Stats Perform News. 

"Some players need two days, some guys need half a year. For example, Moussa Diaby needs three-four months to adapt from France, although he was playing for PSG, to adapt to the Bundesliga.  

"You have to have in mind when you sign players, that not everybody is directly from the first day there.  

"I've followed Chelsea a little bit from a distance, but it's not only Kai or Timo Werner struggling a little bit, it's also the team – they expected more from the whole squad.  

"That's not so easy if it's not working in the team and you come in as a new player. It's much easier if the team is working and you step in your best position.  

"That's a process for Kai, to adapt to England and the Premier League. There is no doubt Kai is a fantastic player and has all the ability to play on the world-class level and although it's probably not his best six months, there is no doubt in my opinion."

"There is a spirit in the team but also the club – a dynamic in the last months and last years. That should lead us one day to a title, that's our big goal."

Bayer Leverkusen are one of Germany's biggest clubs, but not since the 1993 DFB-Pokal have they celebrated silverware.

Leverkusen have come close on numerous occasions in the Bundesliga – runners-up in 1997, 1999, 2000, 20002 and 2011, while they also reached the 2002 Champions League final, succumbing to Zinedine Zidane's iconic volley in Glasgow.

There were also runners-up appearances in the DFB-Pokal – 20002, 2009 and 2020. But an exciting and entertaining Leverkusen, even in the post-Kai Havertz era, are on the right track amid Bayern Munich's domestic and European dominance.

Leverkusen sporting director Simon Rolfes told Stats Perform News: "It's not easy if you're playing with the best team in the world – Bayern – but we have made a step forward and quite close to the top. We want to go forward. If it happens this year, fantastic. But we want to proceed and develop the squad, and mentality."

When star Havertz left for Chelsea at the start of the season in a transfer that could rise to €100million, and Kevin Volland joined Monaco, it left a noticeable hole at BayArena, where the pair scored 30 goals across all competitions in 2019-20.

But led by prodigy Florian Wirtz and a thrilling core of players, including Moussa Diaby, Leon Bailey and Nadiem Amiri, Leverkusen are continuing to challenge this term.

Leverkusen are third in the Bundesliga – three points behind RB Leipzig and 10 adrift of reigning champions Bayern – while Peter Bosz's side are preparing to face Young Boys in the Europa League last 32 and Rot-Weiss Essen in the DFB-Pokal round of 16.

With Havertz having departed, Leverkusen have a better goals/game ratio (2.5) through 26 games across all competitions this season, compared to 1.8 in 2019-20. The club have also improved defensively – goals conceded/game (1.0) and expected goals against (1.0) are better than last term (1.3) and (1.4) respectively.

Collecting 32 points, Leverkusen have played the best first half of a Bundesliga season for seven years – they collected 37 points at this stage in 2013-14.

Leverkusen have also exceeded their xG value of 23.1 to almost nine goals (8.9) – only Bayern have a greater margin between goals and xG (13.9). 

"In general yes because it's a chance for other players to develop and take more responsibility in the team and on the pitch," Rolfes, who was appointed in 2018, said when asked if he was always confident following the exits of Havertz and Volland. "We had the view that there could be other players who could take a step forward. The only thing for sure is Havertz is a world-class player, a fantastic guy and player. It's very difficult to replace him, so we said, it's not our direction to find a replacement for Kai because you will never find that replacement.

"We said okay, we will give our own players the chance to grow, this strategy works out very fast. It's always a risk for sure, but we have the confidence in those players to make a step forward, and also the team. If your superstar is gone, everyone knows we have to give more.

"We try to build-up, play offensive with ball possession, straightforward – the kind of style we showed against Borussia Dortmund [2-1 on January 19] is what we want. We want to have the ball, a lot of clubs and trainers are speaking to play without the ball, in Germany it's very popular, but we want to have the ball and want players who want the ball."

The emergence of teenage sensation Wirtz, and development of Diaby, Bailey, Edmond Tapsoba and Amiri, has further highlighted Leverkusen's successful recruitment and philosophy, which has become synonymous with German clubs.

"You have to have a clear strategy," Rolfes, who made almost 400 appearances for Leverkusen between 2005 and 2015, said. "A clear strategy of recruitment but also your playing style. That's really important for players but also the success of a club – both are strongly connected. For your playing style, you have to sign the right players. Then you have the chance that the players adapt quicker and develop better in your system because they feel comfortable in the way of playing. That's crucial.

"We know the Bundesliga, financially solid, but we are not at the top that we can sign every player, we have to develop players. The strategy is to recruit good players for our style and develop them to the top. Some clubs in Germany are quite successful with this."

"We are focusing on that talent and try to find them," he said. "We analyse millions of data with artificial intelligence, to pre-select and be early. It's not because we know players other clubs do not know, maybe 20 years ago, but everything is transparent. But you have to find them a bit quicker, but also clear in your playing style and what can they develop with your training work, in which areas they can develop in weak points. Because we are not signing players where everything is 100 per cent, we know they have weak points, but we know we have to work with them on that."

Data and AI continue to play a huge role in football, with Rolfes adding: "It's very important and because the data will be better and better, it will become much more important in the future because you will get better results. We are working with our own team on scouting, preparing for next matches – just in our daily work."

The likes of Michael Ballack, Toni Kroos, Bernd Leno and Havertz have all made names for themselves at Leverkusen, and Rolfes continued: "We count on the young players [at Leverkusen]. We give them trust and the opportunity to play. For example, Wirtz, we give him the chance to replace Havertz and not sign another star to put in front of him. That is one thing.

"We have a very professional environment, we really take care of the guys – try to develop them, work on the pitch and prepare them for top football. We have an advantage that the media surrounding is not so big here. That's good for young players to have a familiar environment where they feel very comfortable and less stressful, then try to reach the best level on the pitch."

Wirtz is the heir apparent to Havertz, having made an immediate impact after the 17-year-old swapped Cologne for Leverkusen in 2020.

Having made his debut in May 2020, Wirtz became the youngest goalscorer in Bundesliga history the following month, finding the net in a 4-2 defeat to Bayern after coming on as a substitute. Dortmund's Youssoufa Moukoko has since snatched that record.

Among all players with at least 50 dribbles in this season's Bundesliga, only Augsburg's Daniel Caligiuri has a better dribbles success rate (70 per cent) than Wirtz (65 per cent). 

Wirtz is one of 50 players born in 2003 or earlier to appear in Europe's top five leagues this season. Those 50 players have collected a total of 14 goal involvements – with seven of them coming from Wirtz. 

Among all players in Europe's top five leagues born in 2003 or earlier, Wirtz played the most minutes in all competitions this season (1,579) and had the most goal involvements in all comps (11 – six goals and five assists). 

"I saw him for the first time at 13. Now I have to say, he is playing Bundesliga the same way he was playing at 13, 14, 15, 16 – I followed him all the years. I always said okay, that's the player for us, the player for Leverkusen. That was not a surprise for me when he came to us and adapted very quick to our style," former Germany international Rolfes said.

"It was also one argument I said to him during the transfer. I said, 'you are a player for us, you will develop your skills and strengths much better because that's what we need in our style'. His development is fantastic."

Like Havertz, Bailey could be the next Leverkusen star to leave amid constant speculation over his future.

The 23-year-old winger, who has scored four goals and supplied five assists in the 2020-21 Bundesliga so far, has been linked with the likes of Manchester United and Manchester City and Rolfes is unwilling to sell the Jamaican to just any club.

"He's played a fantastic season," Rolfes said. "He struggled a bit last season, but he is performing at a very high level. A good guy in the squad. He has a chance to score goals for sure. A fantastic technique. That's part of lives also, to sell players but we want to sell to the top eight clubs in the world, but not to other clubs. Sometimes a player will leave us. We have a contract with Bailey but we are quite relaxed."

Diaby is another prime example for Leverkusen, where the accelerating Frenchman has 561 sprints in the league this season, more than any other player. 

The former Paris Saint-Germain speedster has been involved in 15 goals in all competitions in this season (in 26 games) – with his next goal involvement the 21-year-old would already reach his value from his first season in Leverkusen (16 in 39 games). 

"When we extended the contract until 2025, that was a really nice Christmas present to extend the contracts of Diaby, Tapsoba and Wirtz," Rolfes said. "[Diaby] is a key player of our squad. His acceleration and speed is outstanding. He has developed on scoring and assisting. To use his acceleration on a top, top level. He has potential to develop further. I'm very, very happy he is part of our squad."

Meanwhile, Timothy Fosu-Mensah could be the latest success story for Leverkusen, who also completed the signing of Netherlands Under-20 international Jeremie Frimpong from Celtic on Wednesday.

After joining Manchester United's academy in 2014, the 23-year-old called time on his Old Trafford stay in January, and Rolfes said: "He is not so young but the last two years, you had the feeling there was more in the box than there was in the last two years. That's interesting for us, to sign that kind of player where you have the feeling they can reach more. We want to help him.

"Timothy is a really good guy, ambitious guy. I like this. He has the ability, the physicality, very fast, a good technique. A lot of fundamental things that are important for our playing style. Then if the mentality and ambition isn't right, then let's work on that to develop you. I'm convinced Timothy can be the next example for our club."