Andrey Rublev finally got the better of compatriot Daniil Medvedev after a flashpoint involving a courtside camera in the Western and Southern Open semi-finals.

Rublev will now face Alexander Zverev in the decider, having ended Medvedev's bid for a Toronto-Cincinnati double.

Medvedev had never even dropped a set to his fellow Russian in four prior ATP Tour meetings and appeared to be on course for another dominant victory when he took the first set.

But the world number two clattered into a camera early in the second and all momentum was soon lost.

Medvedev complained about the positioning of the camera, claiming it had caused a hand injury and aiming a kick at the lens.

He swiftly called for treatment as his performance started to fall well below his lofty standards, with Rublev finally able to win a set after breaking in an epic 15-minute game.

A series of unforced Medvedev errors allowed Rublev to break again in the decider and seal a stunning 2-6 6-3 6-3 triumph.

Third seed Zverev fought back from a double break down in the final set to progress to the final with a 6-4 3-6 7-6 (7-4) win over second seed Stefanos Tsitsipas.

The epic match lasted two hours and 41 minutes, with Zverev responding strongly after appearing unwell to book his spot in the final against Rublev.

Rublev gets his Daniil degree

Asked to reflect on finally toppling Medvedev, Rublev told Amazon: "It's always tough to play against Daniil and to beat him.

"I think it gives me a bit more confidence that I can play against him, I can compete against him. There are still so many things to improve, but it's like I've passed university."

The victory came as a relief, with Rublev believing he was unfortunate even to be trailing in the first set.

"Inside I was thinking, when I was 6-2, the score shouldn't be like this," he said.

"The points were really tight, some little outs, little mistakes, some good shots from Daniil. The score was not real [in] the first set.

"Even the third set, I won 6-3 but the match was so intense. You saw so many rallies, so many long rallies, and it was so tough.

"It was a super mental match, a super physical match, exactly like a chess match."

Zverev's Novak mentality

Tokyo 2020 gold medalist Zverev had trailed 4-1 in the third set against Tsitsipas, but fought back with two breaks before winning in a tie-break.

"After I did the first break back I thought 'OK I have the chances'," Zverev said during his on-court interview. "I felt like he was not serving bombs. I felt like I was always in the rallies but I was losing the rallies because I was a bit low energy, so I started being a bit more aggressive, a bit of the Novak mentality that I had against him at the Olympics as well."

Zverev has a 4-0 record against final opponent Rublev but he was wary of his opponent.

"Favourite or not, I think if you're in the final, there's no easy opponent," he said. "Today he played incredible beating Medvedev."

World number one Ash Barty reached yet another final on Saturday at the Western and Southern Open, where she will face wildcard Jil Teichmann.

Barty is through to her sixth title match of the season – and first in Cincinnati – after beating Angelique Kerber in straight sets.

In action on the WTA Tour for the first time since winning at Wimbledon, having gone to the Tokyo Olympics in the intervening period, the Australian came through a sloppy spell in the second set to advance 6-2 7-5.

Teichmann is next, taking on Barty for the first time after a stunning run continued with victory over Karolina Pliskova.

The world number 76 had already eliminated Naomi Osaka and Belinda Bencic and was a deserving 6-2 6-4 winner against Pliskova.

Barty finds the balance

Barty had been racing towards victory when she took the opener on Kerber's serve, her second break, and then went 2-0 up in the second.

But Kerber gave the favourite a scare by winning each of the next three games, belatedly finding joy against the Barty serve.

The All England Club champion has won more matches than any other player on tour this year, though, and regained her composure to break twice more for a 39th triumph of 2021.

"It's never, ever a walk in the park against Angie," Barty said. "She's an exceptional competitor and I think early on in that second set she went to another gear and it took me a few games to go with her.

"That was the change – she was able to lift her game and, even though there were some close games, she won the big points early on in the second set.

"I'm glad that I was able to find a way through there in the end.

"I had to find the balance of being aggressive and not getting too passive and letting Angie dictate.

"She moves exceptionally well, puts the balls in difficult positions, and I felt like when I was able to control the court I did a better job.

"In the games I got broken, she just saw too many second serves and was able to be assertive.

"I'm really happy to get through in the end, and to be playing for a title here in Cincinnati is awesome."

'Random' run wears on

Despite facing three seeds in succession, Teichmann has not dropped a set since losing the first against Osaka in the last 16.

Continuing that sequence against Barty will be a tough ask, but few would have anticipated Pliskova being brushed aside quite so easily.

Teichmann herself has no explanation for a sensational run of form.

"It's tough to explain," she said. "When I ask my coaches what they think of me, they always say, 'You're just an unexpected person, you do random things', so I guess that's one of them.

"I'm feeling really, really good here, the conditions, serving good, moving well, when I can I attack, I defend... What I'm feeling here, I cannot even describe it.

"It's a dream. I'm playing centre court, a final against the world number one. I cannot ask for anything else."

Ash Barty reached her sixth semi-final of the year after winning the battle of grand slam champions against Barbora Krejcikova at the Western & Southern Open.

World number one and top seed Barty – the Wimbledon titleholder – dispatched French Open champion Krejcikova in straight sets in Cincinnati on Friday.

Another slam champion awaits Barty in the form of Angelique Kerber, while wildcard Jil Teichmann continued her fairytale run with victory over Olympic gold medallist Belinda Bencic.

Coffee the tonic for in-form Barty

Australian star Barty was too good for Krejcikova, winning 6-2 6-4 at the WTA 1000 tournament.

Barty had to battle from a break down in the second set against the fast-rising Krejcikova, who has shot up from 65th in the world to a career high of number 10 this year.

After extending her season record to 38-7, Barty talked about the importance of drinking coffee in the morning.

"I travel with a French press and an AeroPress, just to have two options. Usually every tournament we go to, one of us has a cafe that we have been to before, so I have got a little section of all my local cafes from the tournaments, so we try and get out to those if we can," she said.

"This year, some places we haven't been able to; some places we have. It's been nice to get some sort of a mixture, but I'm pretty simple. I'm just a black coffee cup in the morning, and then I'm set."

Three-time major champion Kerber is next up after she was 6-4 3-3 ahead before Petra Kvitova retired hurt due to a stomach problem.

Teichmann takes down another star

Unheralded Swiss and world number 76 Teichmann claimed another scalp, this time upstaging countrywoman Bencic 6-3 6-2 in the quarter-finals.

Teichmann stunned world number two Naomi Osaka en route to the quarters and maintained her giant-slaying form in Cincinnati, where 10th seed Bencic became the latest victim.

"We hugged before the match; we hugged after the match," Teichmann said of the Bencic meeting. "We know that once we step on court it's business, it's just another player I have to deal with, and she had the same mindset. At the beginning it's obviously a bit special, but once we're in it, we just look at the game, not looking at the opponent, or at least I do that way."

Teichmann will take on fifth seed Karolina Pliskova, who advanced to her second successive WTA 1000 semi-final after Paula Badosa retired down 7-5 2-0.

Ash Barty and Angelique Kerber set up a blockbuster Western and Southern Open semi-final – but Petra Kvitova suffered a fitness scare ahead of the US Open.

World number one Barty won 6-2 6-4 against French Open champion Barbora Krejcikova, who she also defeated in the fourth round during her Wimbledon title run last month.

Kerber and Kvitova then battled it out for the right to tackle Barty in the last four, but a quarter-final that was building momentum ended prematurely when two-time Wimbledon winner Kvitova found a recent stomach problem too troublesome.

Kerber was 6-4 3-3 ahead in the contest, having recovered from being an early break down in the second set, getting her game together as 31-year-old Kvitova began to suffer.

During an injury timeout, which Kvitova called after the fifth game of the second set, the Czech received a massage to her abdominal region and played on briefly, before walking up to the net to concede the match.

It remains to be seen whether the setback in Cincinnati might have consequences for her involvement at Flushing Meadows, with the US Open due to begin on August 30.

Kvitova wrote on Twitter minutes after coming off court: "I stayed out there as long as I could. I have been struggling with a stomach issue for several days and unfortunately couldn't finish the match today. Good luck Angie - sorry to end it that way - and can't wait for the next battle with you."

Kerber said in an on-court interview: "Of course, this is not the way you would want to win the match. I hope Petra will recover as fast as possible and be ready for the US Open.

"I know she's a big fighter and fights until the last points, so I hope she is not too bad and hope she is fine really, really soon."

Kerber has now won 14 of her last 15 matches, with the exception being her Wimbledon semi-final defeat to Barty.

Barty got through in a more routine manner on Friday, albeit having to battle from a break down in the second set against the fast-rising Krejcikova, who has shot up from 65th in the world to a career high of number 10 this year.

Barty said: "Barbora served exceptionally well early in that second set and was able to take advantage of a service game of mine where I just hit too many second serves.

"I wanted to try and get a little bit more positive on her service games and then try to get myself in the points a little bit more. I'm happy to run away with that one in the end."

Rafael Nadal has curtailed his 2021 ATP Tour season due to a long-term foot injury but insists he is working towards a return.

Nadal, 35, has played only twice since losing the French Open semi-final to Novak Djokovic in May.

The Spaniard skipped Wimbledon and the Tokyo Olympics and had withdrawn from this week's Western and Southern Open before the US Open.

Nadal will not now compete in the final major of the season either, while great rival Roger Federer is also out for an extended period.

It clears a path for Novak Djokovic – the third man tied on 20 grand slam titles – to win a record-breaking 21st championship at Flushing Meadows while completing a remarkable calendar Grand Slam.

Djokovic could yet have competition again in the years to come, though, as Nadal is not yet calling time on a glittering career.

In making his latest announcement on social media on Friday, Nadal revealed he has been dealing with his injury since 2005 but has not let it halt him yet.

"Hello everyone," he wrote on his Twitter page. "I wanted to inform you that unfortunately I have to end the 2021 season.

"Honestly, I've been suffering a lot more than I should with my foot for a year and I need to take some time.

"After having discussed it with the team and family, this decision has been made and I think it is the way forward to try to recover and recover well.

"It's a year that I've missed things that matter a lot to me, like Wimbledon, like the Olympics, how the US Open is going to be now, like many other events that are also important to me.

"And in view of the fact that during this last year I have not had the ability to train and prepare and compete in the way that I really like to do it, in the end, I come to the conclusion that what I need is time to recover, change a series of things, try to understand what has been the evolution of my foot in recent times.

"It is not a new injury, it is an injury that I have had since 2005 and it has not prevented me from developing my sports career during all these years.

"If it is true that I have had a season where things are not going as they should, as we would all like, it is time to make decisions, seek a slightly different type of treatment to find a solution to this problem or at least improve it in order to continue to have options for the next few years.

"I have the maximum enthusiasm and predisposition to do whatever it takes to recover the best possible form to keep competing for the things that really motivate me and the things that I've done all these years.

"I am convinced that with the recovery of the foot, and obviously a very important daily effort, this can be achieved. I will work as hard as I can to make it happen.

"Thank you in advance for all the support, understanding and all your expressions of affection that are very important and more in difficult times like these.

"I promise you what I am going to do is work hard to try to continue enjoying this sport for a while longer. A big hug to all."

Nick Kyrgios, John Isner and Reilly Opelka have been named by Team World captain John McEnroe as his final three picks for the Laver Cup.

The trio join Denis Shapovalov, Felix Auger-Aliassime and Diego Schwartzman for the team event which runs from September 24-26 at TD Garden in Boston.

Laver Cup newcomer Opelka rose to a career-high world number 23 ranking en route to his first ATP Masters 1000 final in Toronto and defeated world number three Stefanos Tsitsipas, who will play for Bjorn Borg's Team Europe.

Isner, who has featured for Team World since the inaugural event in 2017, reached the semi-finals in Toronto and claimed his 16th ATP Tour title in Atlanta at the start of August.

He described the Laver Cup as "a highlight of my year", adding: "To be on a team with guys we're normally competing against is so different and so much fun. We come together so well as a group, the chemistry is awesome and it's such a great environment to be part of."

Australian firebrand Kyrgios is a striking inclusion in Team World's roster, while Team Europe will be without their big three: Roger Federer, Rafael Nadal and Novak Djokovic.

Federer and Dominic Thiem were expected to take part in this year's event, though both were forced to withdraw with injuries.

However, Borg's men still boast six of the world's top 11. World number two Daniil Medvedev leads the line-up, with Tsitsipas and Tokyo Olympics gold medallist Alexander Zverev for company.

Casper Ruud, who collected a 14th win in his last 15 completed matches on tour when he beat Opelka on Wednesday, will feature, while Andrey Rublev and Wimbledon finalist Matteo Berrettini complete the six-man team.

Team Europe have landed the title in each of the three editions of the tournament so far, with Prague, Chicago and Geneva having served as hosts.

Two-time US Open champion Venus Williams has been given a wildcard entry to participate in this year's tournament.

The 41-year-old American will be making her 23rd appearance at Flushing Meadows and a 15th in a row.

Williams, who has not missed a grand slam since Wimbledon in 2013, is one of eight wild card selections for the women's singles draw.

Former semi-finalist CoCo Vandeweghe and Emma Navarro are joined by teenagers Hailey Baptiste, Ashlyn Krueger, Caty McNally and Katie Volynets.

Storm Sanders has been awarded a reciprocal wild card in agreement with Tennis Australia.

Naomi Osaka will be looking to defend her title in New York, with the main draw scheduled to run from August 30 to September 11.

Defending US Open champion Dominic Thiem will miss this year's tournament with a wrist injury that will rule him out until 2022.

The 27-year-old suffered the setback at the Mallorca Open in June and also withdrew from Wimbledon and the Tokyo Olympics.

World number six Thiem won his maiden grand slam at Flushing Meadows last year with victory over Alexander Zverev in a five-set thriller, but he will not get the chance to defend his title in New York.

"Having spent a week training on court, I still felt pain in my wrist and I knew that it was not 100 per cent," Thiem posted in a statement on his Twitter page on Wednesday.

"I went to see my doctors again and we have decided to follow a conservative treatment, giving the injury more time to recover.

"I'm very disappointed not to be able to defend my US Open title and to miss the rest of the season.

"But I know this is what I have to do. I have a long career ahead of me, so I will only come back once I'm fully recovered and in good shape to compete."

Thiem has a record of nine wins and nine losses this season, with his best result coming at the Madrid Open in May when reaching the semi-finals.

Twenty-time grand slam winner Roger Federer last week pulled out of the US Open, which runs from August 30 until September 12, after undergoing knee surgery.

Simona Halep says she is no longer afraid of coronavirus after getting vaccinated and hopes more players will take the jab.

Halep opted against travelling to New York for the US Open last year due to the pandemic before testing positive for COVID-19 last October.

The two-time grand slam champion missed the French Open and Wimbledon this year with a torn calf muscle, but claimed her first win since May at the Western and Southern on Tuesday, beating Magda Linette 6-4 3-6 6-0.

Former world number one Halep revealed she feels much more comfortable back on the circuit after taking the vaccine.

"I don't feel afraid, because I am vaccinated," The Romanian told reporters. "I feel protected. I am taking care. I wear the mask when many people are around."

Players have faced strict protocols since the tour resumed, with the challenges of staying in biosecure bubbles and playing in empty stadiums last year before restrictions gradually eased.

Stefanos Tsitsipas this week said that he would only take the vaccine if it becomes mandatory to play on the ATP Tour after Novak Djokovic stated he hopes it will not become a requirement to take the jab.

Halep hopes fellow professionals take the vaccine so they do not face such strict protocols.

"I don't like the bubbles," Halep said. "I feel very stressed when I'm in the bubble.

"So if people can vaccinate more and more (it) will be better, because we will not have more restrictions anymore."

Simona Halep, a three-time runner up in Cincinnati, claimed her first win since May by overcoming Magda Linette 6-4 3-6 6-0.

The 12th seed has just returned from a calf muscle tear which saw her miss the French Open and Wimbledon, and was defeated by Danielle Collins in Montreal last week.

However, at 1-4 down in the second set she required medical attention for what she described as a "sharp pain" in her right leg, but after a rain delay, the Romanian came out of the blocks to claim a third-set bagel.

Halep progressed to the Round of 32 where she will play American Jessica Pegula.

Sunday's breakthrough National Bank Open winner Camila Giorgo was beaten in straight sets by Pegula 6-2 6-2.

Former world number one Victoria Azarenka needed only one hour and nine minutes to dispose of Ludmilla Samsonova and seal her spot in the last 32.

The Belarussian triumphed 6-2 6-3 over the Russian, dominating her first serve and breaking Samsonova five times throughout the match.

Tokyo 2020 gold medalist Belinda Bencic eased past Marketa Vondrousova 6-3 7-5 continuing her bright recent run, winning in one hour and 27 minutes.

In the final match of the day's play, Caroline Garcia defeated 2017 U.S. Open champion Sloane Stephens 7-6 (9-7) 4-6 6-4 in two hours and 33 minutes.

Dayana Yastremska, Bernarda Pera, Karolina Muchova, Ons Jabeur, Elena Rybakina, Veronika Kudermetova and Coco Gauff were all winners too.