Stefanos Tsitsipas is taking inspiration from the grandfather he has never met after battling through to round two of the men's singles at Tokyo 2020.

Alexander Zverev had an altogether more comfortable progression at Ariake Tennis Park, while home favourite Kei Nishikori earned an impressive upset win.

Felix Auger-Aliassime was unable to make the most of two-time defending champion Andy Murray's withdrawal, but it was a good day for Hubert Hurkacz. 

Here's the pick of the action from day two of the men's singles.

TSITSIPAS OUT TO EMULATE GRANDFATHER

Greek ace Tsitsipas, a French Open finalist this year, had to dig deep for a three-set win over Philipp Kohlschreiber.

Should he manage to win gold in the Japanese capital he would be matching the feat of his grandfather, who won the football competition representing the Soviet Union in 1956.

"I've never had the opportunity to meet him. But my mom told me stories of his career and how he got it," he said. "He kind of inspires me in a way. I know what kind of athlete he was, with all the achievements and all the trophies. I'm proud of him. 

"It's something good, a legacy that is being carried on in the family. I'm happy to be the next in the family to be competing at the Olympics."

ZVEREV LOVING OLYMPICS EXPERIENCE

Fourth seed Zverev coasted past Lu Yen-hsun 6-1 6-3 and spoke of how much he is enjoying being around other German athletes.

"Normally you don't have those guys around that much, you have your friends, of course you have people that are around you, but you don't sleep in the same room as them," he said.

"Yes it is very different but in a way very enjoyable. The Olympics are once every four years, and it’s five years now, so I think everybody is enjoying it and everyone is having the best time that they can."

Nishikori is playing at a fourth Olympics and upset fifth seed Andrey Rublev 6-3 6-4. For the 31-year-old the motivation is simple.

"It's [playing in Japan] something I always dreamed of when I was little," he said. 

"Especially now, with the Covid situation, if I can win as many as I can, I think it will bring better news, that's something I'm trying to do this week."

AUGER-ALIASSIME FAILS TO MAKE MOST OF MURRAY ABSENCE

Auger-Aliassime was scheduled to face Murray before the Team GB star pulled out with a quad issue and will instead focus on doubles.

The Canadian was felled by Murray's replacement Max Purcell, though, the Australian winning 6-4 7-6 (7-2).

Fellow seed Gael Monfils also crashed out but Hurkacz was a 6-2 6-4 victor over Luke Saville, while Diego Schwartzman also made it through.

Casper Ruud secured back-to-back titles by beating Hugo Gaston in straight sets to be crowned Swiss Open Gstaad champion on Sunday.

Ruud won the Nordea Open last weekend and added a fourth ATP Tour title of his career with a 6-3 6-2 defeat of Frenchman Gaston.

The Norwegian took his tally of tournament victories on clay this year to three, having also won the Geneva Open in May, and the 22-year-old will rise to ninth spot in the ATP Race To Turin on Monday.

Ruud saved nine of the 10 break points earned by first-time ATP Tour finalist Gaston, who only won 51 per cent of points behind his first serve.

Gaston, who had never been beyond the second round at an ATP Tour event before this week, was broken twice in each set as the 20-year-old was unable to halt Ruud's brilliant run on clay.

Left-hander Gaston broke straight back after Ruud went 3-1 up in the opening set but failed to back that up with a hold.

Ruud had as many as 16 break-point opportunities but got the job done in an hour and 34 minutes.

World number 30 Cameron Norrie has claimed his maiden ATP title after defeating Brandon Nakashima in straight sets in the final of the Los Cabos Open on Saturday.

British top seed Norrie triumphed 6-2 6-2 in one hour and 23 minutes as he marks another milestone in his career-best season.

Norrie, 25, now has the most wins on the ATP tour this year, going past world number one Novak Djokovic with 35.

The 19-year-old American could not handle Norrie's first serve, while the Briton converted five of his eight break points.

Norrie served for the match with Nakashima pressing him in a tight final game but the top seed rounded out a breakthrough win.

Norrie won 21 of 29 points on his first serve, going at 72 per cent, with Nakashima breaking him once.

Hugo Gaston is one win away from securing his maiden ATP Tour title, but he must overcome in-form Casper Ruud at the Swiss Open Gstaad.

Gaston, ranked 155th in the world, booked his place in his first tour-level final with a 3-6 6-3 6-3 victory over Laslo Djere of Serbia on Saturday.

The 20-year-old had never advanced past the second round at an ATP Tour event before this week. He has now won three matches in a row in a third set.

"I tried to take more time with my game," Gaston said. "I made a lot of mistakes in the first set, so I tried to change my game. My serve was better in the second and third set.

"I am really happy to be in the final. It is going to be a good match, but I will try to enjoy [this] moment."

Ruud, meanwhile, enjoyed a rather more straightforward procession in his semi-final, with world number 249 Vit Kopriva little match for the 22-year-old Norwegian.

The world number 14 needed just 74 minutes to win 6-3 6-0, reaching his second final in as many weeks following his success in Bastad.

Ruud has won 23 clay-court matches already in 2021 and is in the hunt for his fourth career title.

Naomi Osaka lighting the Olympic cauldron will have helped increase the exposure for the sport of tennis around the world, according to Novak Djokovic.

Osaka was given the honour of carrying the torch on the short final leg at the Japan National Stadium before walking the steps to light the flame and end the opening ceremony.

The four-time grand slam champion is the face of the Tokyo Games in her home country, creating extra pressure on her shoulders as she bids to strike gold.

Djokovic appreciates the absences of legendary names Roger Federer and Rafael Nadal is a blow, but he believes Osaka's presence is crucial for tennis in the battle for media coverage at the Games.

"It cannot be better for our sport, you are representing yourself, your country but also your sport in the Olympic Games, you're trying to get the hype and the attention towards our sport as much as you possibly can, so we're all contributing to that in the Olympic Village," Djokovic said when asked about Osaka's role in Friday's ceremony.

"There's a lot of attention towards the tennis players which is great, from the other athletes which is very nice to see, very nice to experience.

"Obviously you don't have Roger or Rafa. They are big stars and legends of our sport, but still there's quite a lot of great athletes, top players. Naomi is a home favourite and a lot of eyes are on her.

"Being at home playing is a lot of pressure, but it's great for our sport just in general to see that there's a lot of attention towards it."

Djokovic was speaking after overcoming Hugo Dellien with ease in his opening outing in the men's singles tournament, the Serbian triumphing 6-2 6-2 in just over an hour.

The quick win allowed the recently crowned Wimbledon champion to avoid staying out for too long in the Tokyo heat, an issue that led to Daniil Medvedev calling for matches to be pushed back to later in the day, allowing players to compete during the evenings when the temperatures have dropped.

"I agree with him 100 per cent," Djokovic said of Medvedev's suggestion. "I actually asked as well.

"My team captain, Viktor Troicki, was speaking to the referee a couple of times. To be honest, I don't understand why they don't start matches at say 3pm.

"I've heard for tennis there is some kind of curfew they have to finish at midnight, but if that's the case, I've just finished the last match and it's not even 5pm, we still have seven hours to play. 

"They have lights on all the courts, they're going to make life much easier for all of us tennis players, I just don't understand why they don't move it. 

"It's actually for the television broadcasters even better, because the later you play, the better it is for the United States and the time zones in Europe.

"I don't know, maybe the ITF (International Tennis Federation) can give you a better answer to why they chose to be played in the middle of the day. I doubt they will change the decision, but we're hoping that they will."

Daniil Medvedev says it is a "joke" that players do not have longer at changeovers but will not "cry about the heat" after coming through his Tokyo 2020 opener, while Novak Djokovic started at a canter as he looks to add the next step of a Golden Slam.

Representing the Russian Olympic Committee, Medvedev appeared fatigued at times in his 6-4 7-6 (10-8) triumph over Kazakhstan's Alexander Bublik at the Ariake Tennis Park.

The conditions in the Japanese capital were sweltering on Saturday but Novak Djokovic was able to keep his cool in coasting to a 6-2 6-2 win against Hugo Dellien.

MEDVEDEV CALLS FOR MORE TIME

Medvedev, who saved three of four break points and now has a 3-0 head-to-head record over Bublik, was pretty pointed about what he feels should be done about the heat.

"Like they do in Mexico, the matches maybe should start at six (pm) because the heat actually gets much, much lighter. We all try to practise at six," said Olympics debutant Medvedev, who next plays Sumit Nagal.

"The fact that we have only one minute between changeovers is a joke. If you ask, let's say 200 tennis players that are here, I think 195 will tell you that one minute is a joke. It should be 1:30.

"But you have to play, that's the Olympics, you go for the medal. You're not here to cry about the heat. It was really tough for both of us. We talked about this after the match on the court. It was unbelievably hot. But you need to get through it."

Fellow Russian athlete Aslan Karatsev (11) defeated Tommy Paul 6-3 6-2 to set up a meeting with Jeremy Chardy, while Lorenzo Sonego (13), Ugo Humbert (14), Fabio Fognini (15) and Alejandro Davidovich Fokina (16) all progressed.

DJOKOVIC UP AND RUNNING

Since winning bronze in Beijing 13 years ago, Djokovic has not had the best of luck at the Olympics – losing in 2012 and 2016 to Juan Martin del Potro on both occasions.

But with a host of big hitters from the ATP absent – including Roger Federer and Rafael Nadal – Djokovic is the overwhelming favourite in Tokyo.

Only Steffi Graf in 1988 from either the WTA or ATP Tour has ever completed a sweep of all four slams and an Olympic gold in a calendar year, and Djokovic needs Olympic gold and victory at the US Open to match the feat.

He needed just 61 minutes here to beat Dellien of Bolivia.

MURRAY SCORES UPSET DOUBLES WIN

Andy Murray is the two-time defending men's singles champion in Tokyo, but struggles with injuries mean it would take a herculean effort to make it three in a row.

But he is also representing Great Britain in the doubles and together with Joe Salisbury upset French second seeds Pierre-Hugues Herbert and Nicolas Mahut 6-3 6-2 in their first time competing with one another.

Murray is not looking too far ahead, though, saying: "You take one match at a time, you know, so a lot of the players here are really motivated to play for their country. 

"This is such a rare opportunity for all of us and I think we all want to do well. So, yeah, just take it one match at a time."

Top seed Denis Shapovalov's Swiss Open Gstaad campaign came to an abrupt end as Vit Kopriva provided a second-round shock to eliminate the Wimbledon semi-finalist.

The world number 10, who has recently been praised by both Roger Federer and Rafael Nadal, took the first set 6-2 with ease before Kopriva, making his ATP Tour debut this week, emphatically fought back 6-3 6-2 to secure a memorable comeback victory.

Number three seed Casper Ruud battled past Dennis Novak 6-4 7-6 (7-5), while Benoit Paire, who only had two ATP wins in 2021 before the Hamburg European Open last week, was 6-4 to the good before Tallon Griekspoor was forced to retire due to injury.

Ruud, who has already won two ATP events in 2021 and three in his career, will now meet sixth seed Paire in the quarter-final stage.

But eighth seed Feliciano Lopez did not enjoy similar success as the world number 96 Mikael Ymer fought past the Spaniard to win 6-7 (6-8) 7-6 (9-7) 6-4 and set-up a quarter-final clash with Kopriva.

At the Umag Open in Croatia, third seed Filip Krajinovic breezed past Radu Albot to record a 6-4 6-2 win.

Krajinovic's countryman and number two ranked player Dusan Lajovic also went through with a 7-5 6-4 win against Bernabe Zapata Miralles.

Novak Djokovic has been burned by high expectations at the Olympics before, so it was little surprise that he should express only guarded optimism on the eve of the Tokyo Games.

The Serbian, who has won the Australian Open, French Open and Wimbledon already in 2021, is chasing the gold medal that would leave him one step away from the first tennis calendar 'Golden Slam' by a man.

Should he triumph in Japan over the next fortnight, Djokovic will head to the US Open in late August needing to win in New York to complete the full set.

Steffi Graf, who in 1988 won all the slams and gold at the Seoul Olympics, is the only player in tennis history to have completed such a sensational season.

Djokovic said such a feat was becoming a "more and more realistic" target, as he spoke in a Serbia team news conference, but the last time he stepped off the singles court at an Olympic Games, he was in tears, having lost in the first round at Rio to Juan Martin del Potro.

There is no danger of Djokovic running into his Olympic nemesis in Tokyo, with Del Potro, who also beat Djokovic in a bronze-medal match at the London 2012 Olympics, not a part of Argentina's squad as he battles back from four knee operations.

Looking at his own prospects for Tokyo and the rest of the year, Djokovic said: "It is still a long way to go ... I put myself in a very good position. But I will take things very slowly and cautiously.

"It's an approach I need to have because in the past I wasn't probably fully experienced in that approach. And I started to feel there were a lot of distractions around that influenced my performance.

"I know there are a lot of things on the line, a lot of history on the line. I'm privileged to be in this position. I worked very hard to be here, with my team, of course. But let's talk about history if everything goes great."

After his singles loss in Rio, Djokovic and Nenad Zimonjic lost in the second round of doubles to Brazilians Bruno Soares and Marcelo Melo.

A bronze from Beijing 2008 is all Djokovic has to show for his Olympics career to date, but he is a hot favourite for the title in Tokyo, where he will start against Bolivia's world number 139 Hugo Dellien.

The 34-year-old Djokovic said he "would be delighted to ask" Graf how she achieved her 1988 clean sweep.

"When I was thinking about her ultimate achievement ... I did not think it... I don't want to say 'achievable', but [I thought] there was a slim chance that someone could make it again, both male and female," Djokovic said.

"But right now it seems more and more realistic. Of course, it is one of my goals and dreams."

Djokovic has neither Roger Federer nor Rafael Nadal as rivals in Tokyo, with Federer missing after reporting a knee injury setback and Nadal electing to give the event a miss.

The 'Big Three' each have 20 grand slam titles now, following Djokovic's hot streak, and the Serbian admits it is unusual for both superstars to be absent.

"I have not experienced too many big tournaments in the past 15 years without Roger and Rafa playing. So it's a little bit strange," Djokovic said. "I'm used to seeing at least one of them. But still, some of the best players in the world are here.

"The guys who are in the top six, seven in the world, they are the biggest competitors or candidates for winning a medal. But potentially I am meeting with them in the later rounds."

After winning Wimbledon for a sixth time, Djokovic surprised many by claiming he could skip the Olympics, but he was reeled in by the appeal of representing his country, perhaps for the final time in the Games.

"Without the key element of any sports events – the crowds, the fans, that energy – it's different, but it is still the Olympic Games," he said.

"I was in a dilemma for a little bit, but I decided to come, and I'm glad because there are many more things that are beautiful about the Olympic Games. So I will try to focus on those things."

Novak Djokovic has leapt from one bubble into another as he attempts to become the first man in tennis history to win all four grand slams and Olympic gold in the same year.

The only men to have won each of the singles majors across their careers, plus Olympic gold, are Andre Agassi and Rafael Nadal, and now Djokovic aims to move to the brink of winning all five in his remarkable 2021 season.

Fresh from dominating at Wimbledon, and with the Australian and French Open titles already in the bag, Djokovic heads into the Tokyo Games as a red-hot favourite, seeking to set himself up to complete a historic campaign at the US Open.

Naomi Osaka will enter the Games with almost as much expectation behind her too, the reigning US Open and Australian Open champion eyeing glory for hosts Japan.

But tennis has thrown up a host of shock results in its short Olympic history. Here, Stats Perform looks at the sport's place in the Games.

WHO'S IN, WHO'S OUT, AND WHAT DOES ALL THIS MEAN?

Serena Williams, Roger Federer and Rafael Nadal have all opted out of the Olympics.

Williams made her mind up prior to suffering a leg injury at Wimbledon, although she is already a member of the career Golden Slam club.

Federer reached his decision after revealing he also suffered a physical setback at the All England Club, and Nadal elected to take a two-month break after relinquishing his French Open title.

Don't expect to see them again at the Olympics, given Williams and Federer will be pushing 43 by Paris 2024, and Nadal will be 38. Federer won a doubles gold with Stan Wawrinka in 2008, but his singles peak was the silver medal he earned in 2012, Andy Murray crushing Swiss hopes in the final at Wimbledon.

Dominic Thiem, Bianca Andreescu, Nick Kyrgios, Simona Halep, Angelique Kerber, Victoria Azarenka and Denis Shapovalov are among other confirmed absentees, with fitness issues a factor for some, less so for others.

The COVID-19 crisis is a mitigating factor in why so many stars are staying away, and directly responsible in the case of some players, such as Britain's Johanna Konta and Dan Evans, who both tested positive recently.

But tennis was only fully restored to the Olympic programme in 1988, after being dropped post 1924, and if players are seen to be favouring the grand slams over the Games, that is not such a great look for the sport.

At a time when the International Olympic Committee has shown it is willing to shake up the sports on its programme, tennis could perhaps do with a headline-making Tokyo 2020.

Murray, the two-time defending men's champion, will target an improbable hat-trick. A hat-trick for the injury-hit former world number one would be a sensation, and Osaka landing gold in the women's tournament would surely be one of the great moments of the Games.

DJOKOVIC FOLLOWING IN THE FOOTSTEPS OF GRAF

When Steffi Graf beat Gabriela Sabatini in the women's singles final at Seoul, it completed what we know now as the calendar 'Golden Slam'. She had already won the Australian Open, French Open, Wimbledon and the US Open, and the feat of the then 19-year-old West German has yet to be repeated.

Now Djokovic is three-fifths of the way to a similar clean sweep of the majors and the Olympics, with the US Open getting under way on August 30 in New York.

He teetered on not going to Tokyo, and perhaps he is to some extent endangering his chances at Flushing Meadows by spending more time travelling and enduring bubble life, while others rest up.

But Djokovic is a fiercely proud Serbian and could not resist a great chance of winning gold for his country. He landed bronze at the 2008 Games in Beijing but in 2012 he lost to Juan Martin del Potro in the bronze-medal match, and a cruel draw at Rio four years later saw him assigned Del Potro in the first round.

Top seed Djokovic bowed out in two tie-breaks to the powerful Argentinian, describing the outcome as "one of the toughest losses in my career".

There is no danger of a hat-trick of defeats to Del Potro, which may help Djokovic. Del Potro has been battling for two years to get back to fitness, undergoing four rounds of right knee surgery in a bid to get back on tour.

RAISING THE BAR AT THE OLYMPICS

How the Olympic village functions in Tokyo will be distinctly different to at previous Games, given the pandemic restrictions in place that could be a real buzzkill.

But in the past there have been countless cases of athletes becoming inspired by their surroundings and going on to perform above their usual level.

It can be a party village, and it can also be an eyebrow-raising experience as global superstars rub shoulders with competitors who might struggle for recognition in their home towns. More than anything, the shared team experience, fighting for a collective cause, can make a middling athlete believe they can be great.

Monica Puig was a massive tennis outsider in 2016 but the then world number 34 won the women's singles, stunning Angelique Kerber in the final after beating Petra Kvitova and Garbine Muguruza en route. That gave Puerto Rico their first ever Olympic gold medal.

In 1992, a tournament that featured the likes of Pete Sampras, Jim Courier, Stefan Edberg and Boris Becker finished with a staggering final match-up of Marc Rosset versus Jordi Arrese, who in his home city of Barcelona was edged out 8-6 in the fifth set by the Swiss world number 43. Nobody would have predicted that head to head for gold.

Similarly, at Athens 2004, Nicolas Massu beat Mardy Fish in the gold medal match of a tournament that featured Federer, Andy Roddick, Carlos Moya and Tim Henman.

In the 1996 Atlanta Games, Lindsay Davenport, who had just turned 20, took inspiration from being the daughter of an Olympian, with dad Wink having played volleyball for the United States at Mexico City in 1968.

Davenport was beginning to make an impact on the WTA Tour but was only the ninth seed at the Olympics, yet she swept through the rounds before sinking Arantxa Sanchez Vicario 7-6 (10-8) 6-2 in the final.

"It's like one of those things I look back on and I'm like, 'Was that me?'," Davenport told The Tennis Podcast last year.

"It doesn't seem like it was real. I'd made the transition to the pro tour pretty well, but I liked hanging out between eight and 16 in the rankings. I was very insecure, unsure of what could I do. I liked doing well but I wasn't sure I wanted to do too well because it seemed really overwhelming to be one of those top players.

"Here I go at 20 years old to Atlanta for two or three weeks, in a setting that seemed so comfortable. Look at all these athletes, you have all different shapes and sizes, you have players that are really working hard but have so much in common and you get to hang out with them, breakfast, lunch, dinner in the village."

Davenport was a future world number one and three-time grand slam singles champion, but at this point in her career being an American at an Olympics in the United States was just a thrill.

"You're sharing this with your team-mates who are some of my best friends in Mary Joe Fernandez, Monica Seles. It was the best time ever," she said.

"By the time the tournament actually started we were like, 'Yeah, I'll go play my match and then we'll go back to the village and we'll hang out', and everything went so fast in those few weeks.

"And there I was left standing, winning at the end because I was so incredibly happy and excited with everything that was going on. I kind of forgot what was my job.

"When it became a reality of even just making the team in '96, it was so huge also for my family with having a second generation Olympian."

Roger Federer is in the draw for the US Open, but it remains unclear whether he will be fit to take part in the final grand slam of the year.

The United States Tennis Association confirmed on Wednesday that Federer was one of six former men's champions to receive direct entry into the draw.

Federer this month withdrew from the Olympic Games, citing a setback with his knee, on which he had two surgeries in 2020.

The Swiss, though, expressed his desire to return the tour, with Flushing Meadows providing his last chance to add to his tally of 20 major titles in 2021.

A five-time winner in New York, Federer has not reached the final at the US Open since 2015.

In the women's singles draw, Naomi Osaka and Serena Williams have each received direct entries into the draw.

Reigning champion Osaka missed Wimbledon having withdrawn from the French Open after the first round to protect her well-being amid a fallout following her decision to not attend post-match media conferences.

Williams is still awaiting a record-tying 24th grand slam title, the 39-year-old forced to retire from her first-round match at Wimbledon because of an injury to her right leg.

Roberto Bautista Agut crashed out to Arthur Rinderknech in the second round of the Swiss Open Gstaad on Wednesday, while fifth seed Federico Delbonis also failed to progress.

Rinderknech, who is ranked exactly 100th in the world, picked up the biggest win of his career in style as he dispatched of second seed Agut with a comfortable 6-2 6-4 victory

In another upset, world number 155 Hugo Gaston laid down an early marker with a first-set demolition of Delbonis, who lost out to eventual winner Pablo Carreno Busta in the Hamburg European Open semi-finals last week, before he triumphed in three sets, 6-0 6-7 (2-7) 7-6 (7-3).

Fourth seed Cristian Garin cruised past Marc Polmans 6-3 6-0 to wrap the match up in less than an hour and seal his fifth ATP quarter-final of 2021.

Another semi-finalist in Hamburg, Laslo Djere survived a second-set scare to eliminate Zizou Bergs with a 6-2 4-6 6-2 win, which sets up a last-eight tie with Rinderknech.

At the Croatia Open in Umag, fourth seed Richard Gasquet battled past qualifier Alessandro Giannessi to secure a 7-6 (7-4) 6-4 victory.

Top seed Albert Ramos-Vinolas also progressed, winning 7-5 6-4 to eliminate Duje Ajdukovic on his home turf.

Fresh off the back of semi-final appearances at the Hamburg European Open, Federico Delbonis and Laslo Djere coasted through their respective first-round matches on the second day of the Swiss Open Gstaad, which included no upsets at the round-of-32 stage.

Delbonis, who is seeded fifth and lost to eventual winner Pablo Carenno Busta last week in Hamburg, cruised to a 6-3 6-3 victory against Leandro Riedi as the Swiss player struggled to make home advantage count.

Seventh seed and loser of the other semi-final in Germany last week, Djere continued his good form and wasted no time in thrashing Brazilian Thiago Seyboth Wild 6-4 6-3.

The other game on day two saw Dennis Novak dispatch of Kacper Zuk 6-4 6-4 and that straight-sets victory means the Austrian will next face the number three seeded player Casper Ruud, who won the Nordea Open last week to secure his third ATP title and second of 2021.

Alongside Ruud, the three other top four seeds - Denis Shapovalov, Roberto Bautista Agut and Cristian Garin - will now enter the draw, after benefiting from byes in the first round of the competition.

There was a surprise at the Croatia Open in Umag, though. Fifth seed Aljaz Bedene went down 6-1- 6-4 to Marco Cecchinato, who will now challenge fellow qualifier Damir Dzumhur to set up a potential quarter-final clash with Richard Gasquet if the Frenchman makes it through his round-of-16 tie.

Benoit Paire made a strong start as the Swiss Open Gstaad got under way on Monday.

Number six seed Paire was a 6-3 7-6 (7-2) winner in his first-round match against Jozef Kovalik.

The Frenchman was not broken in the match, saving all eight of the break-point opportunities he offered up to Kovalik during a competitive 85-minute contest.

Paire's win follows a quarter-final appearance at the Hamburg European Open last week as the 32-year-old begins to recover from a dreadful first half of 2021.

Prior to his run in Hamburg, Paire had only won two ATP Tour matches this year.

Mikael Ymer had to come from behind before he progressed with a 4-6 6-3 6-3 win over lucky loser Enzo Couacaud.

The top four seeds at the ATP 250 event – led by Wimbledon semi-finalist Denis Shapovalov – get a bye through the first round and are therefore yet to begin their campaigns.

At the Croatia Open Umag, meanwhile, Radu Albot came out on top as he claimed a three-set victory over Holger Rune, with top seed Albert Ramos-Vinolas and defending champion Dusan Lajovic not in action on day one.

Kevin Anderson landed his first title since January 2019 as the former Wimbledon finalist triumphed at the Hall of Fame Open on Sunday.

The one-time world number five served 16 aces in a 7-6 (10-8) 6-4 win over 20-year-old American Jenson Brooksby at the tournament in Newport, Rhode Island.

Playing the third grass-court final of his professional career, after being runner-up at Queen's Club in 2015 and at Wimbledon in 2018, Anderson outfought Brooksby to land a seventh ATP title.

Now ranked at a relatively lowly 113th, the 35-year-old South African former world number five saw off top seed Alexander Bublik in the semi-finals before getting the better of Californian prospect Brooksby in the title match.

"It's been a pretty tough run with some injuries," Anderson said, quoted on the ATP website. "But to be back here at the International Tennis Hall of Fame with such history, this couldn't be a better week for me to start, hopefully, my comeback.

"I'm very motivated to get back. But it all starts with each match, and I was able to really grind it out."

Anderson's last title had come on hard courts at the Maharashtra Open in Pune, India, where he got the better of Ivo Karlovic in a match where all three sets went to tie-breaks, and where Karlovic fired 36 aces in a losing cause.

Italy's Matteo Berrettini has become the latest high-profile tennis player to pull out of the Tokyo Olympics after injuring his thigh.

The world number eight, who had a bandaged leg in last week's Wimbledon final loss to Novak Djokovic, joins Rafael Nadal, Roger Federer and Stan Wawrinka in withdrawing from the men's event.

Serena Williams, Simona Halep, Victoria Azarenka, Johanna Konta, Bianca Andreescu and Angelique Kerber are among those to have already announced their decision to skip the women's tournament in Tokyo.

Berrettini, the first Italian to reach a Wimbledon singles final, announced his decision in an Instagram post on Sunday.

The 25-year-old's announcement comes a day after compatriot Francesco Molinari revealed he will not be taking part in the golf event at the Olympics.

"I am extremely disappointed to announce my withdrawal from the Tokyo Olympic Games," Berrettini said.

"I had an MRI scan yesterday on the thigh injury I sustained during Wimbledon and was informed I will not be able to compete for a couple of weeks."

The Olympic tennis events begin on July 24 and run through to August 1.

However, the deadline to name new athletes passed on Friday, so the Italian National Olympic Committee will not be able to name a replacement to join Fabio Fognini, Lorenzo Sonego and Lorenzo Musetti.

"Representing Italy is the biggest honour for me so it is devastating to miss the Olympics," Berrettini added.

"I wish the entire Italian team the best of luck in Tokyo. I will be supporting you all the way."

Despite the flurry of withdrawals, world number one Djokovic confirmed this week that he will enter the Olympic Games.

Djokovic travels to Japan in pursuit of a ground-breaking achievement, the Serbian just two titles – the Olympics and US Open – away from a first men's Golden Slam after triumphing at the Australian Open, French Open and Wimbledon in 2021