Pablo Carreno Busta headlined the casualties at the Winston-Salem Open, where the top seed was shocked in straight sets by Ilya Ivashka.

The 2016 champion, Carreno Busta had his sights set on the semi-finals of the ATP 250 tournament but he suffered a surprise 7-6 (7-2) 6-3 loss on Thursday.

"Of course it's a great feeling. I had a great match today. These conditions suit me," Ivashka said. "I think he had more pressure because he's the top seed so for me it was a good challenge to see what my level is and to compete with these guys, so for me it was a great match."

Carreno Busta – who trumped world number one and 20-time grand slam champion Novak Djokovic to win bronze at the Olympic Games – was not the only seed to fall.

Richard Gasquet and Frances Tiafoe also crashed out in the quarter-finals following defeats to Emil Ruusuvuori and Mikael Ymer.

The only seed to advance to the semis was 15th seed Carlos Alcaraz, who saw off Marcos Giron.

Australian Open chief Craig Tiley is confident the season-opening grand slam will be held in Melbourne next year, despite coronavirus concerns.

COVID-19 continues to wreak havoc around much of Australia, with Victoria and New South Wales both locked down due to outbreaks in the states.

The 2021 Australian Open went ahead, albeit in February instead of January, amid the coronavirus pandemic and without fans for most of the tournament following a snap lockdown of Melbourne.

Novak Djokovic was among the players critical of the conditions athletes endured prior to this year's Australian Open, with strict quarantine measures introduced.

Players, however, as set to spend two weeks in a biosecure bubble prior to the 2022 event, according to Tiley.

"There's a lot of time between now and when we get going but, at this point in time, we're planning on having a two-week bubble, where the players will be able to move freely between the hotel and the courts," Tiley said.

"They're protected, they're kept safe among themselves and safe from the community as well.

"And after those two weeks, they'll come out and be able to compete in the Australian Open in front of crowds."

Stefanos Tsitsipas faces Andy Murray and Ash Barty will take on 2010 finalist Vera Zvonareva in the first round of the US Open.

French Open runner-up Tsitsipas and 2012 champion Murray is one of the standout matches in the opening round at Flushing Meadows.

Top seed Novak Djokovic will start his quest for a calendar Grand Slam against a qualifier in New York and could face a repeat of the Wimbledon final versus Matteo Berrettini in the last eight.

World number one Djokovic, a strong favourite for a record 21st major title with Rafael Nadal and Roger Federer absent due to injury, could do battle with Alexander Zverev at the semi-final stage.

Daniil Medvedev, the second seed, is in the bottom half with Tsitsipas, who he could come up against in the semi-final. Medvedev's first test will come against Frenchman Richard Gasquet.

Barty could come up against Iga Swiatek in the last eight and Karolina Pliskova if she makes it through to the semi-finals.

Simona Halep's encounter with Camila Giorgi is a mouthwatering first-round match, while defending champion Naomi Osaka returns to grand slam action against former US Open junior champion Marie Bouzkova.

Angelique Kerber could be a tough fourth round opponent for Osaka. Close friends Madison Keys and Sloane Stephens meet in another eye-catching first-round match.

There will be no Serena or Venus Williams at the final major of the year due to injuries.

Pablo Carreno Busta sailed into the quarter-finals of the Winston-Salem Open an the top seed was joined by Richard Gasquet.

Carreno Busta – the 2016 champion – was too good for Dominik Koepfer 6-2 6-3 at the ATP 250 tournament on Wednesday.

The Spaniard, who stunned world number one Novak Djokovic to win bronze at the Olympic Games, will meet Ilya Ivashka, who upstaged ninth seed Jan-Lennard Struff 6-2 6-1.

"It was a very good match. I think I played very aggressively today, I made a lot of winners," Carreno Busta said. "I played against him the last two tournaments so it was important to me at the beginning of the match to be very focused and play very aggressive so I think this was a very good match for me.

"I'm feeling really comfortable playing this year, also. We know next we have the US Open but day by day I need the confidence, I need the rhythm. I think that I'm playing at a really good level so I would like to continue this way."

Former world number seven Richard Gasquet saw off third seed Daniel Evans 6-4 7-6 (7-4), Frances Tiafoe defeated Thiago Monteiro 7-5 7-6 (7-2), while fourth seed Marton Fucsovics was sent packing by Carlos Alcaraz 6-3 0-6 6-2.

Top seed Elina Svitolina had no trouble booking her spot in the Chicago Women's Open quarter-finals on the same day Venus Williams and Sofia Kenin pulled out of the US Open.

Svitolina made light work of Fiona Ferro on Wednesday, cruising to a 6-4 6-4 victory at the WTA 250 tournament.

The Ukrainian star and bronze medallist at the 2020 Olympic Games in Tokyo will face seventh seed Kristina Mladenovic in the quarters.

Marketa Vondrousova – the fifth seed, ninth seed Alize Cornet, Tereza Martincova and Rebecca Peterson also moved through from the round of 16.

At Tennis in the Land, second seed Anett Kontaveit secured a quarter-final berth by topping Caroline Garcia 6-3 6-3 in Cleveland.

Meanwhile, Williams and Kenin withdrew from next week's US Open at Flushing Meadows.

Williams – a two-time US Open champion – will not compete in New York due to a persistent leg injury, joining sister Serena in sitting out the year's final grand slam.

"It's super, super, super disappointing," Williams said in a video via her Twitter and Instagram accounts. "I'm having some issues with my leg all this summer, and just couldn't work through it.

"I tried my best here in Chicago [at the WTA 250 Chicago Women's Open], but I just was unable to figure out the equation. And there's been so many times where I've been able to figure it out, even not in the best of my health, but this time, I just couldn't make any miracles work."

Kenin – the 2020 Australian Open champion – withdrew after testing positive for coronavirus.

"Fortunately I am vaccinated and thus my symptoms have been fairly mild," Kenin tweeted. "However I have continued to test positive and thus will not be able to compete at the US Open next week."

"I plan to spend the next several weeks getting healthy and preparing to play well this fall. Thank you all for supporting me. I want to wish all the players the best of luck in New York."

Patrick Mouratoglou says Serena Williams' "heartbreaking" withdrawal from the US Open was the "only possible decision" for the American.

Williams on Wednesday revealed she will not play in her home grand slam due to injury.

The 23-time major champion has not played on the WTA Tour since suffering a torn hamstring at Wimbledon in June and she has not fully recovered.

Mouratoglou, Williams' coach, stated that pulling out of the final slam of the year was the only option for the six-time US Open singles champion.

He tweeted: "Since she had to pull out from Wimbledon, @serenawilliams has been fully committed to her recovery and we've done everything we could so that she could compete at the @usopen. But her body isn't ready. It is heartbreaking, but this is the only possible decision."

Williams posted on Instagram earlier in the day: "After careful consideration and following the advice of my doctors and medical team, I have decided to withdraw from the US Open to allow my body to heal completely from a torn hamstring,

"New York is one of the most exciting cities in the world and one of my favourite places to play – I'll miss seeing the fans but will be cheering everyone on from afar. Thank you for your continued support and love. I’ll see you soon."

Williams, who turns 40 next month, is the latest high-profile withdrawal from the tournament after Roger Federer and Rafael Nadal pulled out through injury

It will be the first time since 1997 that the US Open will be played without Williams, Federer or Nadal.

Serena Williams has withdrawn from the US Open after failing to fully recover from a torn hamstring.

The 23-time grand slam champion, who won six of those titles at Flushing Meadows, has not played on the WTA Tour since sustaining the injury at Wimbledon in June.

She skipped last week's Western and Southern Open in the hope of being ready in time for the her home major in New York, but has now taken the decision to pull out of the event.

"After careful consideration and following the advice of my doctors and medical team, I have decided to withdraw from the US Open to allow my body to heal completely from a torn hamstring," Williams posted on her Instagram account on Wednesday.

"New York is one of the most exciting cities in the world and one of my favourite places to play – I'll miss seeing the fans but will be cheering everyone on from afar. Thank you for your continued support and love. I’ll see you soon."

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.

Lucas Pouille continues to build momentum at the Winston-Salem Open after overcoming veteran Feliciano Lopez in straight sets.

Pouille was on the brink of elimination in qualifying after facing match point before booking his spot in the main draw.

Now, the Frenchman is preparing for the second round following his 6-1 6-4 victory over Lopez on Monday.

Pouille saved all four break points he faced as the former world number 10 claimed his first ATP Tour-level victory since April's Monte Carlo Masters.

Awaiting Pouille in the second round is third seed Daniel Evans, who received a bye in the opening round.

As for 14th seed Richard Gasquet, he prevailed 7-6 (7-4) 7-6 (8-6) against Egor Gerasimov at the ATP 250 event.

Elsewhere, Federico Coria and Jordan Thompson were among the players to progress.

Andy Murray was left in "the strangest situation" he has experienced before a tour match at the Winston-Salem Open following Nick Kyrgios' withdrawal.

Murray had been due to face Kyrgios in an enticing first-round clash in North Carolina, only for the Australian to pull out due to a knee issue.

Former world number one Murray was then drawn against a lucky loser from qualifying, which had only been completed shortly before Murray was due to go on court on Sunday.

The tight turnaround prompted Pierre-Hugues Herbert and Max Purcell to decline the chance to take on Murray, while another option, Yosuke Watanuki, ended up with a direct path to the main draw.

Home hope Noah Rubin, who played his college tennis at the same venue having competed for Wake Forest University, stepped in shortly after his qualifying defeat to Lucas Pouille.

Despite Rubin's best efforts, the challenge proved too much for him as Murray swept to a 6-2 6-0 win, capping a bizarre evening for the three-time grand slam champion.

"It is, by far, the strangest situation I've ever been in before a match on tour," said Murray. "It's pretty rare that you experience something new when you're 17 years into your career.

"I sort of knew at 6:15 that Nick wasn't going to play, but the qualifying was still going on. I was told that if I played a lucky loser, I would play this evening, but if I played against a qualifier the match would be suspended until tomorrow [Monday].

"Then I was told that I drew a lucky loser and I was going to be playing this evening against Pierre-Hugues Herbert, that was like 15-20 minutes after the last qualifying match finished, then Herbert decided he didn't want to play.

"Then they went down the list and none of them, Purcell and Watanuki, they didn't want to play either. And Rubin, who had obviously just finished playing 20 minutes beforehand said, 'yeah I'll do it. I'll play'.

"I kind of had like three opponents in the space of 45 minutes, I was warming up for the match to start at seven and then stopped and then prepared to play Herbert then he didn't want to play then Noah obviously decided but he'd just finished so it was a break and it was just very, very odd sort of 45 minutes, an hour before we went on."

Murray is due to face 13th seed Frances Tiafoe in the second round.

Alexander Zverev believes world number one Novak Djokovic remains the favourite for the upcoming U.S. Open despite the German backing up his Olympic gold medal with victory in Cincinnati.

The German world number four defeated Andrey Rublev in straight sets on Sunday to win the Western and Southern Open, claiming his fourth title of the ATP season.

The 2021 U.S. Open begins next Monday with Dominic Thiem, who defeated Zverev in the 2020 final, withdrawing from the men's draw along with superstar Roger Federer and Rafael Nadal.

Their absences have opened up an opportunity for the in-form Zverev to have a run at the title but the German insisted Djokovic, who he defeated in the Olympic semi-finals, is the player to beat.

"I do think that he's still the favourite," Zverev told reporters after his win in Cincinnati.

"I do think he's going to be playing incredible tennis there. He's going to be fresh, and I think there is also other guys that are in very good form. I think Rublev is in very good form, [Daniil] Medvedev, [Stefanos] Tsitsipas, all those guys are playing great tennis.

"It's definitely going to be an interesting US Open. But I'm also looking forward to it, because I know where I stand, I know how I'm playing, and I hope I can continue the work and hopefully play even better in New York."

Djokovic has not played since Tokyo 2020, where he lost his bronze medal match to Pablo Carreno Busta after his semi-final defeat to Zverev.

The Serbian world number one opted to withdraw from the mixed doubles' semi-final afterwards, citing a left shoulder injury.

"I think Novak will be back. He's obviously going to be the favourite but I think other guys are going to be in great shape,” Zverev said.

"I'm looking forward to the week. Let's see how it goes. But there is still one week to go. I still have a lot of work ahead of me. I have to find my rhythm in New York, as well."

Zverev, who had never won a match in Cincinnati prior to this year's event, has not lost a match since his Wimbledon fourth-round exit to Felix Auger-Aliassime in July.

World number one Ash Barty says her Western and Southern Open title holds her in "good stead" ahead of the U.S. Open which starts at Flushing Meadows next Monday.

The Australian defeated unheralded Swiss Jil Teichmann in straight sets in Sunday's final in Cincinnati in the perfect preparation for the U.S. Open.

Barty has never gone further than the fourth round at Flushing Meadows and did not compete in last year's U.S. Open due to COVID-19 concerns.

The 2021 Wimbledon champion, who also won the 2019 French Open crown, looms as a strong favourite for the women's singles title although she is typically refusing to get carried away.

"I think we're just excited that we've got matches under our belt in tough conditions here in Cincy, and that's put us in really good stead going into New York," Barty said.

"This week it was completely 'non-result-focused'. It was about preparing in the best way possible, knowing that we wanted to be ready for New York in a couple of weeks' time.

"Now that we've only got a week in between, we have played plenty of matches, and now it's about kind of refining as best we can to hopefully be feeling good come the first round in New York and just try and do the best that we can there."

On her favouritism, she added: "There are no certainties in sport, no certainties in tennis. It's just about playing each and every day as best you can as they come, and not focusing or concerning yourself or your self-worth with results."

Riding the wave of her Wimbledon triumph, Barty crashed out of the women's singles in the first round at Tokyo 2020 to Spaniard Sara Sorribes Tormo last month.

The Australian remained grounded after her Cincinnati victory and insisted preparations for the U.S. Open would stay normal.

"I think sometimes after big wins - and I felt it both times after the French Open and after Wimbledon - there's been a little bit of a big crash, more emotionally than anything else, because there's so much invested into that event," Barty said.

She added: "Our practice weeks before grand slams are quite normal. There is nothing fancy, no extra emphasis on anything.

"It's just gauged by how I'm feeling physically, how I'm feeling mentally, and we have had a lot of practice now as a team in being able to read each other and what we think is required.

"Then it's about going out there for the first round, whether it's the Monday or Tuesday, and try to do the best that I can. That's all I can ask of myself."

The draw for the U.S. Open will be revealed on Friday with Barty going in as the top women's seed, with Aryna Sabalenka second seed and reigning champion Naomi Osaka third.

Alexander Zverev claimed his fourth title of 2021 with a 6-2 6-3 victory over Andrey Rublev to win the Western and Southern Open.

The Olympic champion had not won a match in Cincinnati prior to this year's tournament, but Sunday's one-sided final capped a remarkable turnaround for the world number five.

Zverev raced into a 4-0 lead before securing the opening set 6-2 as he produced no errors across the first seven games.

The third seed carried on his domination, breaking Rublev in his opening service game of the second set to pave the way for the 17th ATP title of his career within an hour in the showpiece.

After paying tribute to "his best friend on Tour" Rublev, Zverev added in his on-court interview: "It is incredible that tennis can be back, sport can be back, and we can watch and play this beautiful sport again.

"I normally do not look forward to this week - not winning a single match in seven years - but this has now become one of my favourite times of the year for me, hopefully it can be for the next 10 to 15 years."

The 24-year-old reached the final of the US Open last year, though he will now eye going one step further as the tournament commences at the end of August.

Ash Barty won her first Western and Southern Open title on Sunday with a straight-sets defeat of Jil Teichmann in Cincinnati.

The world number one took her tally to 40 match wins and five WTA Tour titles in 2021 with a 6-3 6-1 victory.

Teichmann, ranked 76th in the world, had won all four of her meetings with top-10 players this season and accounted for Naomi Osaka, Karolina Pliskova and Olympic gold medallist Belinda Bencic during this exceptional week.

Beating Barty, however, proved a step too far. The Australian recovered from some early jitters, winning 85 per cent of points behind her first serve and breaking her opponent five times.

Teichmann's resistance faltered as errors saw her fall 5-3 behind in the opener and Barty won eight straight games to take command of the contest.

Barty needed just one match point to see out the victory, the first at Cincinnati by an Australian woman since Evonne Goolagong Cawley in 1973.

"I think being able to come through and play a really clean week and walk away with the title is probably not what I really expected of myself, but [it is] certainly nice," Barty, who did not drop a set all week, told the Tennis Channel.

Barty will be the firm favourite to win the US Open, where she has never before gone beyond the fourth round. The Flushing Meadows grand slam begins on Monday, August 30.

Rafael Nadal was "practically lame" before he called an early end to his season and has been "stumbling all year round", coach Carlos Moya has revealed.

Former world number one and 20-time grand slam winner Nadal will miss the upcoming US Open but hopes to return in 2022, yet Moya says there are question marks over what the best course of treatment will be for the 35-year-old's foot problem.

In announcing his withdrawal from the rest of the campaign, Nadal declared a foot issue that he has been bothered by since 2005 was behind his decision.

The Spaniard took a break after losing a French Open semi-final to Novak Djokovic, skipping Wimbledon and the Olympic Games.

He attempted to make a return for the hard-court season but lost his second match in Washington to South African Lloyd Harris.

Moya, who was also briefly a world number one, said Nadal had managed to prolong a career that was in doubt 16 years ago, thanks to insoles and treatment.

"But this year the story has changed in many training sessions," Moya said. "He could not finish them and we had to change and ease intensity for the foot, thinking about the tournaments.

"He has been in pain for months and there comes a time when he cannot take it anymore. In the last match he played practically lame.

"The best thing was to stop, rest the foot and refresh the head."

Speaking to Spanish broadcaster Onda Cero's El Transistor show, Moya said: "It is not known where this injury comes from. There is a diagnosis but it is not clear which is the best treatment.

"Rafa's main objective is to regain sensations in his feet and in his head, because stumbling all year round has not helped him."