There seems to be no escaping the number 23 for Serena Williams as she prepares for an emotional final grand slam at the US Open.

It is 23 years since the legendary American won her first major singles title at Flushing Meadows, where she was also crowned doubles champion back in 1999.

Williams has gone on to win an astonishing 23 grand slam singles titles and 14 major doubles titles in an incredible career that is about to come to an end in New York.

One of the all-time greats turns 42 next month and although she is unlikely to bow out by claiming an elusive 24th major singles title in her home major, she is sure to be given a spine-tingling farewell.

Novak Djokovic's absence due to not being vaccinated against COVID-19 has been the big talking point in the men's singles, with Rafael Nadal getting an opportunity to extend his record tally of major successes.

Stats Perform picks out the standout numbers to preview the final major of the year as Emma Raducanu and Daniil Medvedev prepare to defend their titles.

Serena's incredible longevity

Such is the remarkable longevity of Williams' career, defending champion Raducanu and world number one Iga Swiatek were not even born when she won her first major.

Wimbledon champion Elena Rybakina was only a few months old when the iconic Saginaw native beat Martina Hingis in the 1999 US Open final for the first of so many major titles.

Only Chris Evert can boast as many US Open titles as Williams' tally of six in the Open Era, while she has played in a record 10 finals at Flushing Meadows.

The retiring veteran has 106 victories in her home major, a record in the Open Era, and only Martina Navratilova has recorded more wins in a single major - with 120 at Wimbledon.

Williams will be making her 21st main-draw appearance at the US Open, with only her older sister, Venus, bettering that figure in the Open Era as she prepares for her 23rd.

Long-awaited New York return for Nadal 

Nadal has not played at Flushing Meadows since he was crowned champion for a fourth time three years ago, having missed the 2020 tournament amid the coronavirus pandemic and not played last year due to a foot injury.

The Spanish great's hopes of completing a first calendar Grand Slam were ended by an abdominal injury that resulted in his withdrawal from Wimbledon ahead of a scheduled semi-final against Nick Kyrgios.

He could make it three major titles out of four this year in New York, though, where he will be bidding to take his haul of grand slam titles to 23 and move two clear of the absent Djokovic once again.

If Nadal lifts the trophy on Arthur Ashe Stadium, it would give him a record-equalling fifth US Open men's singles title - matching the haul of Jimmy Connors, Pete Sampras and Roger Federer.

Only Bjorn Borg (89.2 per cent) has a higher winning ratio in grand slam tournaments during the Open Era than Nadal's 88.3 per cent among players with at least 100 victories to their name, 

Another record in women's singles?

Teenage Brit Raducanu made history when she became the first qualifier to win a major title last year, beating Leylah Fernandez in the final.

Swiatek has dominated the women's game for much of this year, the highlight being her second French Open triumph.

With the retired Ash Barty, Swiatek and Rybakina taking the singles titles in 2022, there could be four different gram slam champions for a fifth consecutive season - excluding 2020 - and that would be the longest such streak in the Open Era.

Alcaraz to make major breakthrough?

While Nadal will be the Spaniard with the largest burden of expectation on his shoulders, Carlos Alcaraz should be a big threat in New York.

The 19-year-old could become the fifth player in the Open Era to reach at least the quarter-finals in his first two appearances at Flushing Meadows after Ken Rosewall, Arthur Ashe, John Newcombe and Johan Kriek.

Alcaraz has the joint-most ATP Tour titles this year with four, matching Nadal's tally.

Rafael Nadal described Novak Djokovic's absence from the US Open as "very sad" after the Serbian revealed he would not compete at Flushing Meadows.

Djokovic announced he would not be making the trip to New York on Thursday, due to visitors to the United States being required to display proof of vaccination against COVID-19.

The US Open will represent the second grand slam Djokovic has missed this year, after his unvaccinated status saw him deported from Melbourne ahead of the Australian Open in January.

Nadal is one of the most likely players to benefit from Djokovic's absence as he bids to win a 23rd grand slam title, but the Spaniard expressed sympathy for his rival as he prepared to begin his US Open campaign against Rinky Hijikata next week.

"From my personal perspective, it's very sad news," Nadal said. "It's always a shame when the best players in the world are not able to play a tournament because of injuries or because of different reasons.

"It's tough for the fans, tough for the tournament. In my opinion, tough for the players, too, because we want to have the best field possible."

Nadal's clash with Hijikata will represent his first outing at Flushing Meadows since he beat Daniil Medvedev to win the 2019 title, and injuries have caused him to miss four of the last 10 editions of the tournament.

Roger Federer, another of Nadal's great rivals, will also miss the competition after undergoing three knee operations in two years, but the Spaniard believes the major championships can cope with the absences of tennis' aging stars.

"The world of tennis [will] keep going, even if it is not good news for everyone," he added. "The world continues and the tennis will continue after me, after Novak, after Roger.

"Without a doubt, Novak is one of the most important players of the last 20 years, [in] the history of our sport. In a personal way, I feel sorry for him that he's not able to travel here."

Meanwhile, Federer is hoping to return to the court for September's Laver Cup, where he will join Nadal and Djokovic in a star-studded Team Europe line-up, and the Swiss maestro's old foe is desperate to see him make his long-awaited comeback.

"I'm super excited to see Roger again on court, of course," Nadal said. "I hope he's healthy enough to make that happen.

"It has been a long period of time without Roger on court so I really hope that he can manage to be back.

"The most important thing at this stage of his career is the health and the happiness, no? If he's healthy enough and happy enough to be back on the tennis tour, it will be amazing. 

"If not, we can say thanks to him for everything that he achieved. I am confident that we will keep having Roger for a while."

It will be an all-unseeded final at the Winston-Salem Open after Adrian Mannarino eliminated Botic van de Zandschulp 6-0 6-4 in the semi-final.

Van de Zandschulp, the tournament's second seed, was the last seeded entrant remaining in the draw.

In a dominant first set, Mannarino won 80 per cent (12-of-15) of his service points to not allow his Dutch opponent any openings, and he took advantage of some sloppy play.

Van de Zandschulp committed four double faults and 16 unforced errors in the opening set, while Mannarino had no double faults and only one unforced error as the 34-year-old played a veteran's game and allowed his opponent to beat himself.

Overall, Van de Zandschulp committed 20 more unforced errors and five more double faults in the loss.

Mannarino will play Serbia's Laslo Djere in the final, with a chance to win his second career ATP Tour title. His sole title came at the Netherlands' Rosmalen Championships back in 2019. He has a career record of 1-9 in finals.

Djere made it through after yet another grinding affair, defeating Switzerland's Marc-Andrea Huesler 7-6 (7-3) 7-6 (7-5) in two hours and 20 minutes.

All five of his wins this week have required over two hours of court time, with this being his first straight sets result.

In a match that saw each player secure one break of serve, Djere was just slightly better throughout, winning 52 per cent (98-of-189) of the total points, while building a 37-24 advantage in the winners category and serving 10 aces to Huesler's four.

Serena Williams' former trainer Rick Macci has branded Novak Djokovic's omission from the US Open as "a joke".

The three-time winner of the US Open announced on Thursday that he would not play in the event this year, having been denied entry to the United States due to vaccination rules.

It is not the first time Djokovic's non-vaccinated status has hindered his grand slam involvement, having been deported ahead of the Australian Open earlier this year.

Djokovic had hoped to be able to feature, with the US Tennis Association saying it would adhere to any policy change by the US government that allowed him to play, but no changes were announced by the CDC.

While the Serbian will be able to feature next year, Macci has hit out at the regulations and believes it is bad for the sport.

"I don't like it, it's bad for tennis. I'm not losing sleep over it but he played last year, COVID was worse," he said.

"He played the year before, COVID was a lot worse. Now it's in the rear-view mirror but he's not vaccinated, they don't let people in the country, it's a joke.

"It makes no sense whatsoever, it's the government. It makes no sense, zero. I don't think tennis has anything to do with it. It's the government, you've got to be vaccinated to come in, it's unfortunate.

"It applies to, in my opinion, not only the best player in the world but many other people that aren't vaccinated, that maybe it affected your business, visiting relatives or whatever it impacted.

"It's just front and centre because Djoker [Djokovic], who I feel will go down as the greatest player ever to hold a racket, if he's allowed to play tournaments.

"It looks like if you don't get vaccinated, who knows where this is going to go. I'm not in favour of it and I think they should have made a special exception, but if they do it for him, they've got to do it for everybody."

Botic van de Zandschulp is the only seeded player remaining at the Winston-Salem Open, advancing to the semi-final after winning a pair of tiebreakers against Benjamin Bonzi 7-6 (8-6) 7-6 (7-1).

Van de Zandschulp, the second seed, is yet to lose a set in the tournament after straight sets wins against Tallon Griekspoor and Jaume Munar, and he used his dominant serve to get the job done against France's Bonzi.

The Dutchman had 15 aces while Bonzi had three, and he posted 50 winners to Bonzi's 24 in a terrific exhibition of power tennis.

Van de Zandschulp, 26, will face Adrian Mannarino in the semi-final as the 34-year-old seeks his second career ATP Tour title, beating Maxime Cressy 6-4 7-6 (7-3).

Fourth seed Cressy was Mannarino's third consecutive seeded scalp, having also defeated ninth seed Emil Ruusuvuori and eighth seed Albert Ramos-Vinolas to make it this far.

Cressy's 10 double faults and 26 unforced errors shot himself in the foot, as the veteran Mannarino played a clean match, posting two double faults and eight unforced errors.

Serbia's Laslo Djere has taken the scenic route to the semi-final, winning his fourth three-set match of the week as he edged past Richard Gasquet 6-4 3-6 7-6 (8-6) in two hours and 43 minutes.

It comes after a three-hour-11-minute marathon against Jason Kubler in the previous round, and a two-hour-50-minute war of attrition against Joao Sousa prior to that.

Djere will hope to have some more gas in the tank when he meets Switzerland's Marc-Andrea Huesler in the semi-final after he upset 13th seed Jack Draper 6-4 6-4.

Serena Williams will face Danka Kovinic in the first round as the American great begins her final US Open campaign.

It will be a final grand slam for 40-year-old Williams, who has won six singles titles in New York and been a runner-up on four occasions.

Her first singles crown in a major came as a 17-year-old at Flushing Meadows, when she beat Martina Hingis in the 1999 final.

Now the end of a glorious career is beckoning for the 23-time singles major winner, who has also landed 16 doubles grand slam titles.

Kovinic is the world number 80 from Montenegro, with the 27-year-old having only won two matches at the US Open in four previous main-draw appearances.

The winner of that match will likely face Estonian second seed Anett Kontaveit in round two. Kontaveit's first-round opponent will be Romanian Jaqueline Adina Cristian.

Defending champion Emma Raducanu, who was a shock winner last year, faces a tricky first-round assignment against France's Alize Cornet.

Cornet is the tour veteran who beat Iga Swiatek at Wimbledon, ending the Pole's 37-match winning streak, and this will be her 64th consecutive grand slam appearance, a record for WTA Tour players.

World number one Swiatek starts against Italian Jasmine Paolini and could face 2017 US Open champion Sloane Stephens in round two.

Former champion Naomi Osaka, unseeded this year, was paired with Danielle Collins, the 19th seed who was an Australian Open runner-up at the start of the year.

The tournament gets under way on Monday.

Men's defending champion Daniil Medvedev faces American Stefan Kozlov in his opener, while Rafael Nadal, who has not lost a grand slam match all year, faces Australian wild card Rinky Hijikata.

Nadal won the Australian Open and French Open titles before pulling out of Wimbledon ahead of his semi-final against Australian Nick Kyrgios due to an abdominal tear.

That handed Kyrgios a bye through to face Novak Djokovic, who got the better of the Australian, but the Serbian must miss the US Open because his refusal to be vaccinated against the COVID-19 virus meant he would not be allowed to enter the United States.

Djokovic's absence was confirmed shortly before the draw was revealed.

Fast-rising Spanish teenager Carlos Alcaraz begins against Argentina's Sebastian Baez, while fourth seed Stefanos Tsitsipas will face a yet-to-be-determined qualifier.

US Open boss Stacey Allaster said it was "very unfortunate" that Novak Djokovic would have to miss the upcoming grand slam.

Shortly before the draw announcement, it was confirmed that three-time Flushing Meadows champion Djokovic would be absent.

His stance on refusing a COVID-19 vaccination meant he would be prevented from entering the United States, denying the 35-year-old another shot at glory in New York.

Tournament director Allaster said: "Novak is a great champion and it is very unfortunate that he will be unable to compete at the 2022 US Open, as he is unable to enter the country due to the federal government's vaccination policy for non-US citizens.

"We look forward to welcoming Novak back at the 2023 US Open."

The tournament begins on Monday, with Russian Daniil Medvedev defending the title he secured by beating Djokovic in last year's final, when entry requirements to the US were not so restrictive.

Serbian Djokovic has won 21 grand slam titles, one fewer than Rafael Nadal who has already arrived in the Big Apple ahead of the final major of the year.

Nadal moved ahead of Djokovic and clear at the top of the men's all-time list by winning the Australian Open and French Open titles this year, before having to withdraw from a Wimbledon semi-final against Nick Kyrgios because of an abdominal tear.

Djokovic was not allowed to play at the Australian Open at the start of the year, when issues surrounding his visa ended with him being deported from Melbourne on public health grounds due to not taking the vaccine.

Novak Djokovic will play no part in the US Open, the second grand slam he will have missed this year because of his stance on refusing a COVID-19 vaccination.

The Wimbledon champion announced on Thursday, shortly before the draw in New York, that he would not be making the trip to Flushing Meadows.

He posted on social media: "Sadly, I will not be able to travel to NY this time for US Open."

The 35-year-old Serbian, who has won 21 grand slam titles, added: "Good luck to my fellow players! I’ll keep in good shape and positive spirit and wait for an opportunity to compete again. See you soon tennis world!"

Djokovic, who lost to Daniil Medvedev in last year's final in New York, had his route to the United States blocked by red tape this time around.

US authorities are refusing to allow unvaccinated foreign visitors to enter the country. Djokovic, a three-time US Open winner, has been steadfast on his position regarding the vaccine.

The United States Tennis Association (USTA) pledged to adhere to government rulings surrounding coronavirus protocols, despite including Djokovic on the US Open entry list last month.

However, he had first to be allowed to enter the country before he could consider competing, and that was out of the USTA's hands.

In late July, Djokovic said he was "preparing as if I will be allowed to compete"; however, he was unable to travel for the build-up tournaments, and now he will miss the major too.

"Thank you #NoleFam for your messages of love and support," he told his fans on Thursday.

Djokovic was not allowed to play at the Australian Open at the start of the year, when issues surrounding his visa ended with him being deported from Melbourne on public health grounds due to not taking the vaccine.

American great John McEnroe said it was "a joke" that Djokovic should have to miss the US Open too, and called for a solution to be found, but that has not come about.

The current entry rules for international travellers to the United States were not in place when Djokovic was toppled by Medvedev in last year's men's singles final, the result that ended his hopes of a calendar Grand Slam.

Dominic Thiem's run at the Winston-Salem Open came to a halt as Jack Draper claimed a comfortable straight sets victory on Wednesday.

In the first meeting between Draper and Thiem, it was the 20-year-old Brit who sealed his place in the last eight with a routine 6-1 6-4 victory.

Draper charged ahead in the first set, creating five chances to break and taking two of them, while his sole successfully converted break point in the second set paved the way for the Winston-Salem debutant to serve out the match.

World number 55 Draper has now reached three Tour-level quarter-finals this season, while 2020 US Open champion Thiem had been on a run of making it to the last eight in his last three tournaments, in Bastad, Gstaad (where he made the semis) and Kitzbuhel.

Draper did not offer up a single break opportunity, and said: "I was really good behind serve, really solid. In the second set it was tough because he was coming up with some amazing shots. It was a real honour to be on court with Dominic. He's an amazing player.

"I started confidently, I started well. I was hitting through the ball, felt good in the conditions. It was a difficult start because I felt like everyone was supporting Dominic and I knew that I needed to come out confidently and sharp, and that's what I did."

Draper will meet Marc-Andrea Huesler in the quarter-finals, after the world number 102 overcame Ilya Ivashka.

Botic van de Zandschulp is the favourite after Grigor Dimitrov's retirement due to illness with the Dutchman progressing to the last eight by defeating Spain's Jaume Munar in straight sets. He will face Benjamin Bonzi after the Frenchman's 7-5 6-2 defeat of Thiago Monteiro.

Maxime Cressy will face Adrian Mannarino after coming from a set down to beat Lorenzo Sonego 6-7 (4-7) 6-2 7-6 (7-3), while Richard Gasquet and Laslo Djere make up the other quarter-final tie after respective victories over Steve Johnson and Jason Kubler.

Victoria Azarenka will not play in the Tennis Plays for Peace Exhibition at Flushing Meadows on Wednesday, the United States Tennis Association (USTA) has announced.

The former world number one was due to participate in the charity event set up in support of Ukraine ahead of next week's US Open.

The Belarusian's involvement in the exhibition came under scrutiny from Ukrainian player Marta Kostyuk, who subsequently declined the opportunity to compete alongside the likes of Rafael Nadal, Iga Swiatek and John McEnroe.

Azarenka had called for player unity following Russia's Belarus-assisted invasion of Ukraine earlier this year, with the two-time Australian Open winner saying Wimbledon's ban on Russian and Belarusian players made no sense.

Following the recent criticism led by Kostyuk, who was bemused by the presence of Azarenka, the USTA decided it would be in the best interest of the event if she was not involved.

In a statement, the governing body said: "In the last 24 hours, after careful consideration and dialogue with all parties involved, Victoria Azarenka will not be participating in our 'Tennis Plays for Peace Exhibition' this evening [Wednesday].

"Vika is a strong player leader and we appreciate her willingness to participate. Given the sensitivities to Ukrainian players, and the ongoing conflict, we believe this is the right course of action for us."

Top overall seed at the Winston Salem Open, Grigor Dimitrov, won the first set of his opening match against Dominic Thiem 6-0 before being forced to retire due to illness symptoms while trailing 4-2 in the second.

The first set was total domination from the Bulgarian, winning 80 per cent (12-of-15) of the points against Thiem's serve as he breezed through the opening frame in 25 minutes, but after experiencing dizziness and shortness of breath in the second set, he decided to pull the plug on his match after a visit from the doctor.

Thiem will play England's Jack Draper in the next round after he was too strong down the stretch for Italy's Fabio Fognini, winning 6-2 4-6 6-1.

Meanwhile, it was relatively smoother sailing for second second Botic van de Zandschulp in his all-Dutch matchup against Tallon Griekspoor, converting both of his two break point opportunities to win 7-6 (7-5) 6-3.

Earlier in the day, in-form Belarusian and 11th seed Ilya Ivashka used his powerful serve to overwhelm Germany's Peter Gojowczyk 6-4 6-2. 

Ivashka will meet Switzerland's Marc-Andrea Huesler next after the world number 102 passed a stiff test against Sweden's Mikael Ymer, with his 6-4 6-4 win likely elevating him into the top-100 when the next rankings are released.

Richard Gasquet at 36 years young upset 20-year-old Italian Lorenzo Musetti 7-6 (7-5) 4-6 6-1, and he will play Steve Johnson next after the big American defeated Spain's Pedro Martinez 7-6 (7-2) 6-2.

Serbia's Laslo Djere needed almost three hours to get the better of Portugal's Joao Sousa 4-6 6-3 7-6 (7-5), and Djere will play Australia's Jason Kubler after he handled South Korea's Kwon Soon-woo 7-5 6-2.

The other two Aussies in action were less successful, as John Millman fell 6-4 6-4 to Spain's Albert Ramos-Vinolas, and James Duckworth went down 6-3 6-3 against Maxime Cressy.

Finland's rising star Emil Ruusuvuori was disappointing in his 6-4 6-1 loss to France's Adrian Mannarino, and fellow Frenchman Benjamin Bonzi also got the job done against England's Kyle Edmund 6-4 7-6 (7-5).

In the late session, 15th seed Jaume Munar defeated Tseng Chun-hsin 6-3 6-4, and in the last match of the night, Lorenzo Sonego beat Alejandro Tabilo 7-5 6-1.

John McEnroe has called Novak Djokovic's potential absence from the US Open over his vaccination status a "joke".

The United States does not currently allow those who have not received the COVID-19 jab into the country, putting the unvaccinated Djokovic in real danger of missing this year's edition of the tournament he has won three times.

The Serb has already missed the Australian Open this year because of his lack of vaccination, while also missing tournaments at Indian Wells in California, as well as the Rogers Cup in Canada.

He did however win his 21st Grand Slam at Wimbledon earlier this year, and McEnroe believes Djokovic should be allowed to play at Flushing Meadows as he chases down Rafael Nadal for the most Grand Slam titles in history.

Ahead of the tournament in New York, McEnroe told reporters: "No, I don't think it's fair. I think it's a joke.

"I would have had the vaccine and gone and played but he's got very strong beliefs and you have to respect that. 

"At this point, in the pandemic, we're two and a half years in, I think people in all parts of the world know more about it, and the idea that he can’t travel here to play, to me is a joke."

On whether Djokovic's decision not to get the vaccine could affect his competition with Nadal and Roger Federer to become the most decorated male player ever, McEnroe replied: "That's the question that we all want to know the answer to.

"Obviously, Rafa Nadal has benefited from that. These three guys are already above everyone else. So, it makes it extremely interesting to see these two go at it and then you think of Roger Federer but he's been hurt for a while."

However, McEnroe believes Djokovic can overcome his vaccination status to win more titles, adding: "Who's to say [Djokovic] can't do it for another couple of years?

"Let's say that he wins three or four more. That's not impossible, by any means. Despite this, he can still get to 25. I think it's made it more complicated to do it because that has to wear on you mentally.

"Training this past month or six weeks not knowing whether he's going to play, that's going to put a strain on you mentally just as it was when he got thrown out of Australia. I think it took him three, four months to get his head right."

A spectator at the Wimbledon final who Nick Kyrgios accused of looking like she had consumed "about 700 drinks" is taking legal action against the Australian.

Polish lawyer Anna Palus was temporarily ejected from Centre Court last month after Kyrgios claimed she was drunk and putting him off during his defeat to Novak Djokovic.

He said to the chair umpire between points: "She's drunk out of her mind in the first row.

"The one who looks like she's had about 700 drinks talking to me in every single point."

Ms Palus has instructed her solicitors, Brett Wilson LLP, to start defamation proceedings against the 27-year-old and she is prepared to take the case to the High Court if there is no "prompt resolution" to the matter.

She said in a statement released by solicitors Brett Wilson LLP: "On Sunday 10 July 2022 I attended the final of the Wimbledon tennis championships with my mother.

"It was an event we had been looking forward to for some time. During the course of the final, Nick Kyrgios made a reckless and entirely baseless allegation against me. 

"Not only did this cause considerable harm on the day, resulting in my temporary removal from the arena, but Mr Kyrgios's false allegation was broadcast to, and read by, millions around the world, causing me and my family very substantial damage and distress.

"I am not litigious, but after much consideration, I have concluded that I have no alternative but to instruct my solicitors Brett Wilson LLP to bring defamation proceedings against Mr Kyrgios in order to clear my name.

"The need to obtain vindication, and to prevent a repetition of the allegation, are the only reasons for taking legal action. Any damages recovered will be donated to charity.

"Given the extant claim, I am unable to comment further on the events of the day in question. I hope that Mr Kyrgios will reflect on the harm he has caused me and my family and offer a prompt resolution to this matter. However, if he is unwilling to do this, I am committed to obtaining vindication in the High Court."

The clock is ticking on Novak Djokovic's prospects of playing at the US Open, two days out from the draw at Flushing Meadows.

Wimbledon champion Djokovic, who lost to Daniil Medvedev in last year's final in New York, has his route to the United States blocked by red tape at present.

US authorities are refusing to allow unvaccinated foreign visitors to enter the country, and barring a change of policy on that front, his hopes appear forlorn. Djokovic, a three-time US Open champion, has refused to accept any COVID-19 vaccine.

The United States Tennis Association (USTA) has pledged to adhere to government rulings surrounding coronavirus protocols, despite including Djokovic on the US Open entry list last month.

He remains on that list for now, but there was an indication that the US Open may not be expecting to see Djokovic when a promotional poster was revealed this week that featured four top women players and four leading men.

The men selected were defending champion Medvedev, 22-time grand slam winner Rafael Nadal, Australian Nick Kyrgios and Spanish teenager Carlos Alcaraz. All were archive pictures, so Djokovic could easily have been selected for the advertising campaign.

His exclusion prompted an angry response on social media from some fans of the 35-year-old Serbian, with one saying it would be "a failed tournament if he doesn't participate in it".

The US Open draws are due to take place on Thursday ahead of the start of the tournament on Monday.

Leading players are already assembling on site, with Medvedev, Serena Williams, Nadal, Alcaraz, Simona Halep and Andy Murray among those with practice sessions booked in for Tuesday.

For Djokovic to be allowed into the United States, it appears he would require a sudden change of entry rules from law-makers, or he would have to be considered suitable for an exemption.

In late July, he said he was "preparing as if I will be allowed to compete"; however, he has not been able to travel for the build-up tournaments.

On Instagram, Djokovic's last tennis-related post came on Monday night as he sent a congratulatory message to shock Cincinnati champion Borna Coric, telling the Croatian: "Bravo king! Totally deserved. All the effort and patience paid off. Go ahead and good luck."

Djokovic was not allowed to play at the Australian Open at the start of the year, when issues surrounding his visa ended with him being deported from Melbourne on public health grounds due to not taking the vaccine.

American great John McEnroe told Tennis 365 in July it was "crazy" that Djokovic should have to miss the US Open and called for a solution to be found.

The current entry rules in the United States were not in place when Djokovic was toppled by Medvedev in last year's men's singles final, ending his hopes of a calendar Grand Slam.

Dominic Thiem defeated J.J. Wolf to set up a showdown with top seed Grigor Dimitrov in the second round of the Winston-Salem Open.

Thiem showed signs of returning to his best with runs to the last eight or better in three tournaments in July, but the 2020 US Open winner was in danger of falling at the first hurdle in North Carolina when he lost the first set against the American wildcard.

But Thiem, a debutant in the competition, bounced back, and after a long rain delay he prevailed 6-7 (5-7) 7-5 7-6 (8-6), and he will now face Dimitrov, who is seeking a first trophy since 2017.

The Austrian had to save two match points during a last-set tie-break, and said afterwards: "First of all I'm super happy to get that win, [my] first win on hard courts since a very long time, since March 2021, I guess.

"It was not easy at all today with the rain delay, coming back out there at 11:15 p.m. It was very late. I had trouble [getting] into the match again.

"But luckily I raised the level a little bit in the third-set tie-break and compared to Kitzbuhel, where similar stuff happened with the rain, the luck was on my side today."

Second seed Botic van de Zandschulp also learned of his last-32 opponent on Monday, with Tallon Griekspoor beating fellow lucky loser Taro Daniel 7-6 (7-3) 6-3.

Last year's beaten finalist Mikael Ymer ensured a safe passage through, meanwhile, thanks to a 6-2 6-3 victory against Federico Coria.

Australia's James Duckworth also advanced with a 4-6 6-3 7-5 (7-5) comeback win over compatriot Thanasi Kokkinakis, while Kyle Edmund saw off Michail Pervolarakis 6-2 7-5.

Sixth seed Nikoloz Basilashvili was a big-name exit, as he went down to Thiago Monteiro.