Frances Tiafoe will face Alexander Zverev in the Vienna Open final after storming back from the brink of defeat to beat Jannik Sinner.

Sinner was on the cusp of another final after his triumph in Antwerp last weekend when he led 5-2 in the second set, but qualifier Tiafoe roared back to win 3-6 7-5 6-2 on Saturday.

Italian Sinner had moved into the last qualifying position for the ATP Finals by beating Casper Ruud to reach the semi-finals in the Austrian capital and appeared destined to extending his winning run.

The 49-ranked Tiafoe had other ideas, winning five games in a row to force a deciding set.

Tiafoe maintained his momentum, breaking twice in the final set to complete an astonishing comeback and leave seventh seed Sinner shellshocked.

Second seed Zverev earlier marched into his fifth tour-level championship match of the season with a 6-3 6-3 defeat of Spanish teenager Carlos Alcaraz.

Zverev, who this week secured a 50th tour-level win of the season and a 300th of his career, needed only 68 minutes to knock Alcaraz out.

The German said: "I finally found my rhythm from the baseline because I was really struggling.

"I didn't feel the ball well and I spent some time on the court after the match yesterday and warmed up for an hour and a half before the match today and I finally got it."

Marin Cilic and Taylor Fritz will do battle in the St Petersburg Open final following contrasting wins over Botic Van de Zandschulp and Jan-Lennard Struff respectively.

Cilic did not face a break point in a 6-3 6-3 victory over Dutchman van de Zandschulp, while fought back to defeat Jan-Lennard Struff 5-7 6-1 6-3.

Top seed Andrey Rublev crashed out of the St Petersburg Open after a straight-sets defeat by Dutch qualifier Botic van de Zandschulp in the quarter-finals.

A recent US Open quarter-finalist, world number 69 Van de Zandschlup claimed the first top-10 win of his career on Friday.

The 26-year-old also advanced to the semi-finals of an ATP event for the first time.

There, he will face 2011 champion Marin Cilic, who was a 6-4 3-6 6-3 winner over third seed Roberto Bautista Agut.

Denis Shapovalov was another big-name casualty in Russia, the second seed going down 4-6 3-6 against world number 53 Jan-Lennard Struff.

Although, there were better fortunes for fifth seed Taylor Fritz. The Indian Wells semi-finalist is yet to drop a set this week after prevailing 6-4 6-2 against John Millman.

Elsewhere, Matteo Berrettini was the victim of another upset at the Erste Bank Open in Vienna.

The Wimbledon champion went down 1-6 7-6 (7-2) 6-7 (5-7) following a two-hour 40-minute battle with Carlos Alcaraz.

Reaching his first ATP 500 semi-final, the Spanish teenager claimed another big scalp having defeated Stefanos Tsitsipas at Flushing Meadows last month.

However, second seed Alexander Zverev remained on course for a fifth title of the season, as he claimed his 300th tour-level win.

The Australian Open finalist beat Felix Auger-Aliassime 6-4 3-6 6-3, avenging his fourth-round defeat by the Canadian at Wimbledon in July.

Jannik Sinner continued his push for an ATP Finals spot with a straight-sets defeat of Reilly Opelka in the first round of the Vienna Open, while Carlos Alcaraz exacted revenge on Andy Murray.

Sinner won his fourth title of what has been an outstanding season for the Italian in Antwerp last weekend and is only 110 points adrift of Hubert Hurkacz in the battle for the final place in the season-ending event in Turin.

Murray did the 20-year-old a favour by knocking Hurkacz out of the ATP 500 tournament in the Austrian capital on Monday and seventh seed Sinner eased to a 6-4 6-2 win over American Opelka two days later.

Sinner, who will overtake Pole Hurkacz if he reaches the semi-finals this week, won 93 per cent of points behind his first serve and did not face a break point in a resounding win and will play Dennis Novak in the second round.

Murray beat Alcaraz at Indian Wells this month, but the 18-year-old rising star from Spain turned the tables on the three-time grand slam champion with a 6-3 6-4 second-round win in Vienna.

Former world number one Murray struggled with his serve and was broken five times as he made an early exit.

Third seed Matteo Berrettini beat Nikoloz Basilashvili 6-7 (5-7) 6-2 6-3 to reach the third round, while Diego Schwartzman, Gael Monfils and Lorenzo Sonego moved into the second round.

In the St Petersburg Open, defending champion Andrey Rublev beat Ilya Ivashka 6-4 6-4 to reach the quarter-finals along with Denis Shapovalov, a 2-6 6-3 6-0 winner against Pablo Andujar.

Jan-Lennard Struff also moved into the last eight, with Karen Khachanov and Marin Cilic securing first-round wins.

The top two seeds will do battle in the European Open final following commanding victories for Jannik Sinner and Diego Schwartzman on Saturday.

Sinner, the number one seed, moved into his fifth final of the season with a 6-2 6-2 defeat of Lloyd Harris in Antwerp.

The 20-year-old Italian, who is in the hunt for a maiden ATP Finals spot, dominated Harris from the baseline and saved all three break points he faced.

There were only 16 unforced errors from the racket of the composed Sinner, who will be bidding to win his fourth title of the season on Sunday.

Sinner said: "I am very happy to be in the final. I just love playing here and love playing indoors, so hopefully I can play a great match again tomorrow."

Schwartzman ended 20-year-old American Jenson Brooksby's impressive run with a 6-4 6-0 victory.

The Argentinian struck 15 winners and secured five breaks as he marched into the championship match.

Russian second seed Aslan Karatsev will come up against Marin Cilic in his first final on home soil after knocking compatriot Karen Khachanov out of the Kremlin Cup.

Karatsev beat Khachanov 7-6 (9-7) 6-1, while sixth seed Cilic – a two-time winner of the tournament in Moscow – got the better of Ricardas Berankis 6-3 6-4.

Jenson Brooksby enhanced his growing reputation and set up showdown with Diego Schwartzman in the European Open semi-finals.

The 20-year-old American, who took a set off Novak Djokovic and rattled the world number one at the US Open, is shaping up as potentially his country's biggest hope for the future in the men's game.

Californian Brooksby crushed Spain's world number 44 Alejandro Davidovich Fokina 7-5 6-0, and second seed Schwartzman awaits after the Argentinian took down another 20-year-old American, Brandon Nakashima, scoring a 6-4 6-2 quarter-final win.

Schwartzman is the man who ended Andy Murray's hopes at the tournament in Antwerp.

Brooksby, who had to win two qualifying matches to reach the main draw, said: "Tomorrow will be a great match. I'm really looking forward to it. I'll get some rest tonight and get ready to battle again tomorrow."

The other semi-final will see Italian top seed Jannik Sinner take on South African seventh seed Lloyd Harris following their respective straight-sets wins over Arthur Rinderknech and Marton Fucsovics.

There will be an all-Russian semi-final at the Kremlin Cup in Moscow, after Aslan Karatsev and Karen Khachanov won through to the final four.

Second seed Karatsev sank the hopes of Frenchman Gilles Simon, breaking serve five times on the way to a 6-4 6-3 win, while third-seeded Khachanov edged out Australian John Millman. A 7-5 7-6 (7-4) grind featured 19 aces by Khachanov, the 2018 Kremlin Cup champion, who saved four set points in the second set.

Marin Cilic thrashed Pedro Martinez 6-1 6-2 to set up a tussle with Ricardas Berankis, the Lithuanian ending Adrian Mannarino's run with a 6-2 7-6 (7-1) success. Frenchman Mannarino had stunned Russian top seed Andrey Rublev in the previous round.

Karen Khachanov revealed he felt the nerves of playing in front of a home crowd as he marked his return to Moscow with a comeback victory in the Kremlin Cup.

Handed a bye for the opening round, third seed Khachanov made home advantage count in his first match as the Russian defeated Australian world number 50 James Duckworth 3-6 6-3 6-1 to reach the quarter-finals on Wednesday.

Khachanov – Olympic Games silver medallist, who triumphed in Moscow three years ago – will face another Australian, John Millman after he defeated Illya Marchenko 6-1 5-7 6-4 at the ATP 250 tournament.

"It always feel great to be back in your hometown, in a tournament where everything started for me as a professional tennis player," world number 31 Khachanov said.

"[This is] where I won my first matches, I got my first points. Since then, it's always great to come back home to see a crowd, [get] home support. It's also little bit more nervous, of course. But I always enjoy playing at home."

Khachanov was joined in going through to the last eight by sixth seed Marin Cilic – a two-time Kremlin Cup champion who overcame Tommy Paul 7-5 6-3.

At the European Open in Antwerp, top seed Jannik Sinner downed fellow Italian youngster Lorenzo Musetti 7-5 6-2 in the duo's first meeting as professionals.

"We never practice together, so it was kind of a new match," Sinner said post-match.

"He's an incredible player. He's a very great talent, so I hope we will have a couple of more matches on the pro tour, and obviously I'm very happy about my level today."

Arthur Rinderknech upstaged eighth seed Dusan Lajovic 6-3 4-6 6-2 to set up a quarter-final tie with Sinner, who is in the hunt for a fourth title of the season and a place at next month's ATP Finals in Turin.

Another emerging talent, qualifier Jenson Brooksby, bettered US Open quarter-finalist Botic van de Zandschulp 6-2 6-0, with Alejandro Davidovich Fokina sending third seed Cristian Garin packing 4-6 6-3 6-3.

Arthur Rinderknech continued his fantastic season by defeating Federico Delbonis at the European Open, while Marin Cilic battled through in the Kremlin Cup.

Rinderknech, who sits 65th in the world rankings, had not recorded a Tour-level victory before 2021 but has now triumphed 15 times after cruising past Delbonis 6-4 6-4.

The Frenchman will meet eighth seed Dusan Lajovic in the second round in Antwerp, after the Serbian downed Richard Gasquet 7-6 (7-3) 6-1 on Monday.

The other first-round clash in Belgium saw Alexei Popyrin capitulate in the third set as he succumbed to a 4-6 6-3 0-6 defeat against world number 62 Botic van de Zandschulp.

Americans Jenson Brooksby and Brandon Nakashima also booked their places in the main draw. Brooksby defeated Norbert Gombos 6-4 6-2, while Nakashima overcame Pierre-Hugues Herbert 6-2 6-4.

Meanwhile in Russia, Cilic – who has claimed the crown in Moscow twice previously – recovered from a first-set scare in his round-of-32 tie with qualifier Damir Dzumhur, eventually triumphing 6-7 (4-7) 6-1 6-1.

John Millman experienced similar difficulties, with Benjamin Bonzi claiming the first set before the Australian succeeded 6-7 (5-7) 6-4 6-3 to set up a potential second-round match against fifth seed Alexander Bublik.

Three-time Grand Slam winner Andy Murray has bemoaned his inconsistency within matches after bowing out of the Winston-Salem Open in the second round to Frances Tiafoe on Tuesday.

The 13th seeded American triumphed in one hour and 49 minutes over the Scot, who entered the event as a wildcard and had beaten lucky loser Noah Rubin in the first round.

Tiafoe won 7-6 (7-4) 6-3, saving three set points in the first set, before winning the tiebreak and taking command in the second.

Murray sent down 10 aces across the match but struggled on his second serve and on return.

"The positive thing is that I moved well and served well but my level is up and down with no real consistency," Murray said after the match in North Carolina.

"There are moments in matches where I play well and then I make mistakes or miss returns. I wish I wasn't doing that.

"My level is around 50 or 60 in the world. It's frustrating because if wasn't moving great and not feeling good physically then I would be a bit easier on myself. But when I'm winning a low percentage of second-serve points, that's got nothing to do with the physical side of things."

Sixth seed Marin Cilic also bowed out, losing 4-6 7-5 6-4 to Belarussian Ilya Ivashka, who sent down 16-13 aces.

Fifth seed Alexander Bublik was also bundled out, going down 6-2 7-6 (7-5) to Finland's Emil Ruusuvuori.

Top seed Pablo Carreno Busta dropped a set but edged past Kwon Soon-Woo 6-3 3-6 6-4.

British third seed Dan Evans came from behind to beat Lucas Pouille, while fourth seed Marton Fucsovics won in straight sets over Yosuke Watanuki.

South African Lloyd Harris booked a second-round date with Rafael Nadal at the National Bank Open after a straight-sets win over Canadian qualifier Brayden Schnur on Monday.

World number 49 Harris eased past Ontario-born Schnur 6-3 6-2 in one hour and 17 minutes in Toronto.

Harris sent down nine aces, winning 78 per cent of points on his first serve, converting four from four break points on return.

Nadal is a five-time champion in Toronto, winning the previous two editions in 2018 and 2019.

Marin Cilic, who won his first title for three years in Stuttgart, beat Albert Ramos-Vinolas 6-2 4-6 6-3 in two hours and 13 minutes.

The 32-year-old will face sixth seed Casper Ruud in the next round.

Fabio Fognini also needed three sets to progress, battling from behind to defeat Jan-Lennard Struff 6-7 (2-7) 6-2 6-4 to set up a meeting with Andrey Rublev.

Ugo Humbert impressed in his straight-sets defeat of Lorenzo Sonego and will next face third seed Stefanos Tsitsipas, while qualifier James Duckworth beat Taylor Fritz to secure a showdown with Citi Open winner Jannik Sinner.

Alexander Bublik defeated Briton Dan Evans in straight sets to earn a second round meeting with top seed Daniil Medvedev, while Australian John Millman will face 11th seed Gael Monfils after beating Ricardas Berankis.

Reilly Opelka came from a set down to win over Australian Nick Kyrgios, while Tommy Paul also fought back to beat Canadian Vasek Pospisil.

Daniil Medvedev vowed not to let his fifth-set lead slip after a stunning Wimbledon comeback against Marin Cilic – even though he admitted he was "basically destroyed" in the first two sets on Saturday.

Cilic, the runner-up at the 2017 championships, was two sets to the good in the third-round match on Court 1 against the second seed.

Yet Medvedev, who won his first Tour title on grass in Mallorca this year, responded in style to win a grand-slam match after losing the opening two sets for the first time.

The Russian triumphed 6-7 (3-7) 3-6 6-3 6-3 6-2 to stretch his grass-court winning streak to seven matches and reach Wimbledon's second week for the first time in his career.

Medvedev took David Goffin to five sets at this tournament two years ago only to suffer defeat, and he was worried such a scenario could repeat itself when his 5-0 lead in the decider quickly became 5-2.

"It was an unbelievable match," he said on court. "I think tennis fans always enjoy watching players come back from two-sets-to-love down and for it to be five sets. I certainly do so when I watch tennis on the TV.

"It's my first comeback [from two sets down], and actually what's amazing is against David Goffin at Wimbledon in 2019, I was two-sets-to-love down and I had a break in the fifth set, but I lost. So when I left the court after the fourth set today, I told myself, 'It's not going to be another one of those'.

"So I'm really happy. When I was 5-0, 40-0 up at the end and Marin came back to 2-5, I thought to myself, 'Again!' Marin is an amazing player and for the first two sets he basically destroyed me."

Medvedev joined compatriots Andrey Rublev and Karen Khachanov in the second week, making this the first year in which three Russian men have reached this stage at Wimbledon in the Open Era.

Medvedev will face 14th seed Hubert Hurkacz next and could meet Roger Federer in the quarter-finals.

Marin Cilic cited his experience as the key to sealing a first ATP Tour title in three years against Felix Auger-Aliassime at the Stuttgart Open on Sunday. 

The Croatian, who did not drop a set all week, hit seven aces on his way to a 7-6 (7-2) 6-3 win in one hour and 50 minutes. 

At 32, Cilic is the third-oldest Stuttgart champion in the Open Era (since April 1968) behind Roger Federer, 36, and Barry Phillips-Moore, 33.

It brought up his 19th ATP Tour title and he believes the knowledge he has amassed in his career was crucial to overcoming an opponent 12 years his junior. 

"Experience plays a big part, especially on grass," he said in quotes reported on the ATP website. 

"The conditions can be difficult; the court plays quite quickly. I felt this was a good chance for me to give it my all, keep my intensity. 

"Even though some games were up and others down, that was a big part of my victory today.

"It was a very important win. I played two semi-finals and did not win a title since 2018, also on grass at Queen’s. 

"Winning here brings out joy for me, good confidence and a good feeling.

"I felt like I was playing good tennis these last few weeks. Winning here is a great way for me to continue my form and it gives me a good sign for Queen's and Wimbledon. 

"It is a joy to win my first title with my family here for the first time at any tournament."

Auger-Aliassime, who has now lost all eight ATP Tour finals he has contested, had no complaints with the result. 

"Today, I am not facing a final, I am facing Marin Cilic; it is two different things," he said. 

"There have been times when I have not played my best then I felt I was not playing well, but this time around, I felt like it was close. 

"Overall, though, I think he was the better player."

Marin Cilic is relishing the chance to win a 19th career title when he takes on Felix Auger-Aliassime in Sunday's Stuttgart Open final.

The world number 47 was 6-3 1-0 up against Jurij Rodionov in Saturday's semi-final when his opponent retired due to injury.

Cilic eliminated top seed Denis Shapovalov in the quarter-finals and now faces a tough test against world number 21 Auger-Aliassime, who beat Sam Querrey in the other semi.

"I'm feeling really good and very excited to be in the final after a period that I didn't reach a final," said Cilic, who lost to Roger Federer in the second round of the French Open.

"I think this has been a very positive week. I have played good tennis and served really well.

"Considering it is a shorter season, with one week less, for me, it was great to play this week. Losing in Paris to Roger Federer gave me more time to prepare for the grass."

The former Wimbledon runner-up and 2014 US Open champion added: "I haven't enjoyed being at a tournament this much in a long period of time, because it is the first time my son, wife and I are together at one tournament.

"The set-up in Stuttgart is really nice. There is a lot of grass and open space around the hotel for my son to play and it is so much fun having them around."

Auger-Aliassime did not face a single break point and hit seven aces in his 6-4 7-5 victory over Querrey, which lasted an hour and 19 minutes.

The Canadian third seed won 16 of his 18 first-service points in the second set and has yet to drop a set in this week's tournament.

It is the second time Auger-Aliassime has reached the Stuttgart final, having finished runner-up to Matteo Berrettini two years ago.

The 20-year-old has lost all seven of his ATP Tour singles finals to date so is longing to be a champion for the first time, even as he tries to stay cool about the prospect.

"You have to be focused all the time," Auger-Aliassime said. "Things can turn around quickly but I was able to do well today.

"There are no expectations. There will be the final tomorrow and other tournaments are coming up and I will try to keep my level as much as I can."

Top seed Denis Shapovalov failed to reach the semi-finals of the Stuttgart Open as his busy Friday ended with defeat to Marin Cilic.

Shapovalov had earlier completed a rain-delayed match with Feliciano Lopez, winning in three sets.

However, the Canadian was beaten in two tight sets by former US Open champion Cilic, who prevailed 7-5 7-6 (7-3).

"I felt I was applying a little more pressure during that first set and I capitalised on the couple of break points, which was definitely big, just to give me a bit of extra momentum," Cilic said.

"I also had the two match points at the end of the second set, didn't convert them, but played a really good tie-break. You always have to expect tough battles against top guys like Denis and it was like that today."

Cilic will face Jurij Rodionov after the Austrian came from behind to stun fourth seed Alex de Minaur, a player ranked 120 places above him, 3-6 6-3 7-6 (7-4).

Shapovalov's Canadian compatriot Felix Auger Aliassime remains in the draw, though, going through to the last four with a 7-6 (7-5) 7-6 (10-8) win over Ugo Humbert in which he hit 17 aces.

Auger Aliassime, the lone seed left in the tournament, is hoping to repeat his run to the final in 2019. Standing in his way will be the sizeable figure of Sam Querrey, who ended wild card Dominic Stephan Stricker's superb tournament.

Teenager Stricker had match point at 5-4 in the second set but Querrey fought back to progress 6-7 (4-7) 7-6 (7-4) 6-3. Querrey won all 14 of his first-serve points in the final set.

Teenager Dominic Stephan Stricker produced the shock of the day at the Stuttgart Open as he knocked out second seed Hubert Hurkacz in the round of 16.

The 18-year-old wildcard, ranked 335 in the world, claimed a straight sets victory courtesy of tie-breaks, as had been the case in his previous outing against Radu Albot.

And his reward for a 7-6 (7-5) 7-6 (7-5) win over a man placed 315 places higher than him in the men's rankings is a quarter-final tie against Sam Querrey.

The American sealed his passage into the last eight by beating qualifier James Duckworth 6-4 7-6 (9-7) on Thursday.

Top seed Denis Shapovalov's place in the next round remains in doubt going into Friday after the Canadians clash with Feliciano Lopez was cut short by rain with both men having taken a set.

The winner of that final set will face former world number three Marin Cilic, who comfortably beat Nikoloz Basilashvili 6-3 6-2.

Another Canadian also remains in the draw in the form of third-seeded Felix Auger-Aliassime after his 6-3 7-6 (7-4) win over Lloyd Harris.

There, he will face sixth seed Ugo Humbert after his straight sets win over wildcard entry Yannick Hanfmann.

The quarter-final line-up is completed by fourth seed Alex de Minaur, who beat compatriot Jordan Thompson, and Jurij Rodionov, whose progress was aided by Peter Gojowczyk's first-set retirement.

There were no shocks at the Stuttgart Open on Tuesday as Marin Cilic and both seeds advanced.

The grass-court swing got under way with four main-draw matches but little drama in Germany.

One-time Wimbledon finalist Cilic staved off the only two break points he faced against wildcard Rudolf Molleker and seized all five opportunities of his own.

A 7-5 6-3 win was enough to set up a second-round meeting with fifth seed Nikoloz Basilashvili, who beat Dustin Brown in the top half of the draw.

The defeated pair were the only home hopefuls in action, while number six seed Ugo Humbert and Lloyd Harris each also progressed.