The career of Carlos Alcaraz could be one that takes up a great deal of space in the record books, and he is getting started early.

Not yet old enough to buy a stiff drink in a New York bar, the 19-year-old was the toast of Flushing Meadows after a late-night win over Marin Cilic that ran into the early hours of Tuesday.

That five-set win against the 2014 champion, combined with the shock exit of Rafael Nadal at Frances Tiafoe's hands, has raised expectations that Alcaraz could scoop a first grand slam title on Sunday.

Should he land that breakthrough major, there will be another feather in his cap, making Alcaraz the youngest world number one since the ATP rankings were established in 1973, and the first teenager to hold down top spot. He has climbed from 32nd at the start of the year to his current position of fourth on the list.

Nadal is poised to go to number one, which he last held in February 2020, unless Alcaraz or 23-year-old Norwegian Casper Ruud reach the title match. They are the only two players remaining in the draw who can clamber to the top ranking, which Daniil Medvedev will relinquish after his fourth-round exit to Nick Kyrgios.

If both reach the final, the champion will go to number one.

In the city that never sleeps, Alcaraz completed a 6-4 3-6 6-4 4-6 6-3 win over Croatian Cilic at 02:23 local time, three minutes short of matching the latest finish in US Open history, shared jointly by three matches: Mats Wilander vs Mikael Pernfors (1993), John Isner v Philipp Kohlschreiber (2012), Kei Nishikori v Milos Raonic (2014).

The victory on Arthur Ashe Stadium made Alcaraz the youngest man to reach back-to-back US Open quarter-finals since Australians Lew Hoad and Ken Rosewall both achieved the feat before turning 19 in 1953. It was called the US Championships in that era.

Alcaraz has won a tour-leading 48 matches in 2022 and has become the youngest man to reach three grand slam quarter-finals since Michael Chang over 30 years ago.

However, he next faces a player making his own history.

Alcaraz's quarter-final opponent is a recent nemesis: Jannik Sinner, the 21-year-old Italian who beat him in round four at Wimbledon and again in the final of the clay-court event in Umag, Croatia, at the end of July.

"I played a couple of times against him," Alcaraz said. "He's a great player, really tough one. I lost twice in two months [to him] so I will have to be ready for this battle against Jannik."

There is a victory that Alcaraz could point to, having defeated Sinner on an indoor hard court at the Paris Masters last November, but they have never played on an outdoor hard court, which is where they will do battle on Wednesday.

Sinner has now reached the quarter-final stage of all four majors, becoming the youngest man to pull off that feat since a 20-year-old Novak Djokovic completed the set in 2008.

The last-eight duel with Alcaraz could be a sizzling clash, albeit Alcaraz and Sinner had some recharging to do on Tuesday after both were pushed to five sets in round four, in Sinner's case by Ilya Ivashka of Belarus. Alcaraz now has a 6-1 win-loss record in five-set matches.

Nobody remaining in the men's quarter-finals has a slam title to their name, and Alcaraz will hope he continues to have the backing of the crowd in Queens.

He said after fending off Cilic: "Of course, the support today in Arthur Ashe was crazy. After losing the fourth set, it was tough for me to come back in the fifth set, to stay strong mentally. But the energy I received today made me win."

Rafael Nadal's loss to Frances Tiafoe opened up a host of possibilities including a first-time world number one and maiden grand slam winner as the top three's domination of men's singles continues to weaken.

World number three Nadal bowed out in the fourth round to 22nd seed Tiafoe 6-4 4-6 6-4 6-3 on Monday, while third seed Alcaraz triumphed over Marin Cilic 6-4 3-6 6-4 4-6 6-3 in a match that went to almost 2:30am local time.

Cilic was the last remaining male player with a grand slam title to his name, meaning this year's US Open will bring a new major champion.

There may also be a first-time world number one too, with Alcaraz guaranteed to claim the top rank if he wins the US Open title.

Fifth seed Casper Ruud will rise to world number one if he lifts the US Open crown at Flushing Meadows on September 11 too.

If both fall short of the final, Nadal will reclaim the top ranking from 2021 US Open champion Daniil Medvedev, who lost in the fourth round to Nick Kyrgios.

Alcaraz could also scale the rankings summit should he reach the final, assuming Ruud misses out.

Daniil Medvedev knows he has not performed to the best of his abilities at grand slams this season after his US Open title defence was ended by Nick Kyrgios.

Medvedev, who will also concede his spot at the top of the ATP's world rankings, has only won one of the four finals he has reached in 2022.

His record in the majors is a particular frustration for the 26-year-old. After losing to Rafael Nadal in the Australian Open final, Medvedev has reached the fourth round at Roland Garros and the same stage at Flushing Meadows, while The All England Club's ban on Russian and Belarusian athletes prevented him from competing at Wimbledon.

With Novak Djokovic unable to play in New York due to his COVID-19 vaccination status, Nadal, Carlos Alcaraz or Casper Ruud will become the world number one after the US Open's conclusion on Sunday.

"I mean, now that you say it, I remember it," Medvedev said in a press conference when asked how it felt to give up the number one spot.

"That's not nice because honestly after such a match, when you lose in a grand slam... I'm trying to look good here, but I'm disappointed.

"[I'm] not going to cry in the room, but I'm a little bit disappointed. For a few days I'm going to be just a little bit sad, looking at my phone, my laptop or watching some series.

"Yeah, it was not the first thing on my mind walking after the match, saying, 'Damn, I will not be the world number one anymore' – I actually don't know which place I will be. Probably three or four. I guess Carlos will pass me. I don't know actually.

"But that's motivation, try to do better. Obviously it was the last slam of the year. I didn't do well enough. Didn't win in Australia when I had the chance. Didn't get the chance to play at Wimbledon.

"Roland Garros, lost in the fourth round. Here, fourth round. Yeah, I should do better, should get more points if I want to be world number one again."

Medvedev went down 7-6 (13-11) 3-6 6-3 6-2 to Kyrgios, who has a 4-1 winning record against the Russian.

Asked if he thought it was Wimbledon finalist Kyrgios' best display against him, Medvedev suggested the Australian came close to replicating the form of greats Nadal and Djokovic.

"Yeah, it was a high-level match," he said. "[I] played Novak, Rafa. They all play amazing. Nick played kind of their level, in my opinion.

"He has a little bit different game because he's not a grinder in a way, [but] at the same time he can rally. He's tough to play.

"He has an amazing serve. He plays well, has every shot. It was a really high-level match from him.

"If he plays like this until the end of the tournament, he has all the chances to win it, but he's going to get tough opponents."

Nick Kyrgios took the opportunity to discuss the low points of his career after his victory over Daniil Medvedev, admitting he never thought he would have the chance to return to his best form.

Kyrgios conceded just one set to Medvedev in the 7-6 (13-11) 3-6 6-3 6-2 triumph at the US Open on Sunday.

It appeared during the first set tiebreaker that he was on the verge of one of his famous meltdowns, with a couple of racket slams and plenty of abuse towards his own box, but he steadied and fought back after a poor second frame.

Speaking to the media after the match, Kyrgios admitted the tiebreaker was do-or-die, saying: "I feel like if he'd got that first set, it was going to be pretty much an impossible task for me to come back and win."

This year's Wimbledon runner-up was humble and respectful when discussing the talent of Medvedev, and despite his muted celebration, highlighted what a big deal it is for him to perform well under the bright lights in New York.

"I didn't over-celebrate. It's only the fourth round, I've got quarter-finals [next]," Kyrgios said. "But it was an amazing experience obviously taking down the number one player in the world on Arthur Ashe Stadium.

"I don't really like to celebrate too much after that because I know that if I played him nine more times, he's probably getting on top of me the majority of the time.

"I hadn't won a match on Ashe before this week, now I've won two against two quality opponents, and I feel like I've been able to showcase [my talent].

"There's a lot of celebrities here, a lot of important people here watching. I wanted to get on that court and show them I am able to put my head down and play and win these big matches.

"For the tennis world I think it's important as well. People were really starting to doubt my ability to pull out matches like this at majors. I'm really proud of myself honestly because it hasn't been easy dealing with all the criticism."

Kyrgios continued to discuss how he feels he is perceived by the public and the media, saying it was more a feeling of relief than ecstasy when he finished the job.

"I feel like I'm more just proud of the way that I've bounced back after everything, honestly," he said. "I've been in some really tough situations mentally, and in some really scary places.

"Obviously if you look at it on paper, I probably wasn't expected to win that match. Maybe take a set or two if I'm lucky, give the people a show.

"It's a great win, but I come off the court and I'm just almost relieved that it's over because there's just so much pressure every time I go out on court, so much expectation, so much unpredictability of what I can do.

"I just sit there in the locker room after and I'm just super proud of the performance, because there was really a time where I didn't think I was capable of producing and doing this any more.

"I guess I'm just more relieved, and I'm super proud."

Nick Kyrgios is through to the quarter-final after a terrific 7-6 (11-13) 3-6 6-3 6-2 win over world number one and reigning US Open champion Daniil Medvedev.

It was a match that had all of the usual Kyrgios antics as he seemed to lose his cool during the first set tiebreaker, slamming his racket multiple times while repeatedly yelling at members of his entourage.

But he was able to work his way through it, saving three set points, before sealing the opening frame in 64 minutes with his fourth set point. Kyrgios relied on his dominant serve and limiting his errors, with just one double fault and 11 unforced errors with 21 winners.

The momentum from winning the set kept Kyrgios from spiralling mentally, but he became sloppy in the second, committing four double faults with only three aces, and he had 12 unforced errors with seven winners. It was the only set he had more than one double fault and more unforced errors than winners.

Zverev's ability to return in the second set was the difference, lifting his return point success rate from 33 per cent in the opener to 48 per cent to break twice and even up the match.

It had all the makings of a Kyrgios meltdown, but where he would usually begin to unravel and force desperate power shots to shorten points, he instead settled into the battle and refocused on getting into the net.

After only going to the net five times in the second set, he tripled that in the third, winning nine-of-15 attempts while not allowing a single break point opportunity. Kyrgios only created one break point chance for himself, and he took it with both hands to go up two sets to one.

In the fourth, Kyrgios was able to break again with his first opportunity early on, and with his serve switched on and firing he would only allow one chance for Zverev to break back, but he snuffed it out before going on to secure a second break and the victory.

Of their five career meetings, Kyrgios has now won four, and he will now get the benefit of the number one seed's path through the tournament. Next up, he will face 27th seed Karen Khachanov in the quarter-final as he searches for his first career grand slam title.

Data Slam: Kyrgios accomplishes feat not seen since 1987

Kyrgios is the first player since 1987 to defeat the world number one twice in the same year, with Australian compatriot Pat Cash the last to do it.

It is also the first time an Australian has defeated a world number one in a grand slam since Kyrgios himself, back in 2014 as a 19-year-old against Rafael Nadal at Wimbledon.

ACES/DOUBLE FAULTS

Kyrgios – 21/7

Medvedev – 22/2

WINNERS/UNFORCED ERRORS

Kyrgios – 53/38

Medvedev – 49/19

BREAK POINTS WON

Kyrgios – 5/7

Medvedev – 3/8

Nick Kyrgios believes no other player will be able to emulate the career Serena Williams has enjoyed, after the grand slam great confirmed her retirement.

Williams went down 7-5 6-7 (4-7) 6-1 to Ajla Tomljanovic – Kyrgios' former partner – on Friday in the third round of the US Open.

That brought an end to her playing career, though the 40-year-old suggested she would leave the door open for a potential return.

Kyrgios, who defeated J.J. Wolf to set up a contest with reigning men's champion Daniil Medvedev, is in awe of what Williams has achieved, as he ranked the 23-time grand slam champion alongside Rafael Nadal, Roger Federer and Novak Djokovic.

"She's had a career that I don’t think no one else will emulate," Kyrgios said.

"You've got a couple on the men’s side who are trying to catch her in grand slams, but Nadal, Serena, Federer, Novak, these are once in a generation athletes – I wouldn't even put myself in the same category, ever.

"It's a special moment for her, she played extremely well, she won two matches and nearly got on top [against Tomljanovic], it's a hell of a way to go out.

"I just appreciate what she's done and I'm sure everyone in this building does as well."

After beating Wu Yibing, world number one Medvedev said of Williams: "That was a crazy match, it was close to being three hours.

"It's definitely a pity that she lost. If it's the last match of her career, it was definitely an amazing match and she was really close to winning.

"Ajla played at a great level, it was not easy against the crowd and it was a high-level match."

Williams bows out with the most grand slam wins in the Open Era of any player, male or female.

Daniil Medvedev has described both himself and US Open fourth-round opponent Nick Kyrgios as "electric", but says the pair share more "respect" than friendship.

The world number one will continue his men's single title defence against the Australian in the last 16 at Flushing Meadows after a 6-4 6-2 6-2 Win over China's Wu Yibing.

The pair are set to meet for the fifth time on the ATP Tour, with Kyrgios holding an impressive 3-1 record over the Russian in their previous four encounters, including in the final of the 2019 Citi Open.

But Medvedev defeated the former on home turf at the Australian Open earlier this year, in arguably the biggest clash between the duo.

Speaking ahead of the pair's encounter, Medvedev stressed he does not see the pair as friends, but he has strong admiration for his opponent's game and is impressed at how he has revived his fortunes this year.

"I don't think we are friends," he added. "I feel like we respect each other a lot. We are both quite electric. You never know what's going to happen in the future

"Nick is a little bit different from other tennis players on the court. That's his choice. That's his life. I'm not the one to judge. I feel a lot of respect for him."

Asked if he is surprised at Kyrgios' improved form following a first grand slam final this year at Wimbledon, Medvedev added: "To be honest, yes.

"We all knew that he's capable of doing big things. We always knew on [his] day, he is capable of beating anyone.He [has] proved it many times, against the biggest players in the world."

Kyrgios, meanwhile, is relishing another battle on a big occasion, adding that his attempts to seize victory against the odds of public opinion allow him to "thrive".

"You want to be in those moments," he said. "I want to be playing on the biggest stadiums in the world in front of millions of people broadcasted globally. That's where I want to be. That is why I work hard.

"It makes it even sweeter. I know a lot of people don't want me to succeed. I know a lot of people hate my game, the way I do things, the way I go about it. I always thrive on it. I never want to forget all the things people say.

"I always carry this chip on my shoulder. Win or lose, I'm proud of how far I've come. I think that's where every tennis player wants to be, playing the best players in the world in the best stadiums in the world."

World number one Daniil Medvedev was levels above his third-round opponent Yibing Wu on Friday, defeating him 6-4 6-2 6-2 to set up a highly anticipated clash with Nick Kyrgios in his next match.

While Medvedev had the clear power advantage – finishing with 10 more winners and 11 more aces – he also allowed Wu to beat himself, with 18 unforced errors and three winners in the opening set.

Despite his early wastefulness, Wu still created six break point opportunities in the opening set, but could only capitalise on one. It would be his last break of the match as Medvedev tightened the screws down the stretch.

The Russian took the first four matches of the second set to take away any hope Wu had of fighting back into the contest, and in the third set Medvedev's serve really hit top gear.

He faced no break point opportunities in the final frame as he converted over 70 per cent of his points on both first serves (13-of-18) and second serves (eight-of-11), while Wu's errors returned, with 15 and just four winners.

Against Kyrgios next, Medvedev will be looking for his second win against the Australian in their fifth meeting. In their two matches this year – and their only two since 2019 – Medvedev won in four sets at the Australian Open, before Kyrgios got one back at the Canadian Open.

ACES/DOUBLE FAULTS

Medvedev – 12/5

Wu – 1/0

WINNERS/UNFORCED ERRORS

Medvedev – 26/27

Wu – 16/42

BREAK POINTS WON

Medvedev – 6/12

Wu – 1/8

Nick Kyrgios was far too good J.J. Wolf in the third round of the US Open on Friday, not having his serve broken a single time in the 6-4 6-2 6-3 victory.

Kyrgios dominated the match with his serve, racking up 21 aces to Wolf's five, and of the seven break point opportunities the Australian allowed, he saved all seven.

His return game was sharp as well, creating 11 break points and converting five, and he used it to break away in the second set, rattling off five consecutive games to comfortably go up two sets to love.

The third set was more competitive as Kyrgios had a pair of double faults, and more unforced errors (17) than winners (16), but he ultimately had too much firepower for the 23-year-old American.

After coming back from a love-40 deficit, saving four break points in the game, Kyrgios put the finishing touches on the straight sets win with another break of serve to seal it.

With the win, he books his spot in the fourth round, where he will meet world number one Daniil Medvedev.

Kyrgios has won three of the four career meetings between the pair, including their most recent fixture at the Canadian Open.

ACES/DOUBLE FAULTS

Kyrgios – 21/5

Wolf – 6/1

WINNERS/UNFORCED ERRORS

Kyrgios – 36/32

Wolf – 20/26

BREAK POINTS WON

Kyrgios – 5/11

Wolf – 0/7

US Open reigning champion and top seed Daniil Medvedev has put the pressure on 22-time grand slam winner Rafael Nadal who he believes is the frontrunner for the Flushing Meadows title.

Medvedev endured a 10pm start time playing on Arthur Ashe Stadium after Serena Williams' three-set win over Anett Kontaveit on Wednesday evening to defeat Arthur Rinderknech 6-2 7-5 6-3 in two hours and 11 minutes in the second round.

The Russian was not happy with his level early in Wednesday's match, admitting he did not adjust seamlessly to the late start time, but said he worked into it.

The win books a third-round clash with Chinese qualifier Wu Yibing but Medvedev was pressed on the favourites for the men's singles title in the absence of Novak Djokovic this year.

Medvedev claimed his maiden major at last year's US Open with victory over Djokovic in the final, while he lost to Nadal in a memorable five-set Australian Open decider earlier this year.

"First of all, I don't want to put pressure on anybody, but I think Rafa is a big favourite also," Medvedev told reporters.

"He won the last time he played here against me actually. He won two slams this year. I think Novak is better on grass, but Rafa didn't play.

"He actually didn't lose in a Grand Slam this year. He retired [in the Wimbledon semi-final against Nick Kyrgios], which is not the same.

"In my opinion Rafa is big, let's call it like this, I don't want to say favourite, big favourite, he's definitely big figure in this tournament.

"Then for sure there are many other good guys. I'm happy to see my name sometimes in the odds or something like this because I'm like, that's great. That means that I play some good tennis.

"Being amongst the favorites just brings me more motivation to try to do well."

Medvedev compared his 2022 form in New York (he beat Stefan Kozlov in the first round in straight sets) to last year's when he won the title, admitting he did not feel he was going as well as 12 months ago at this stage.

"These two matches felt a little bit less good comparing to last year, but at the same time I know I already played a lot of Grand Slams," he said.

"That's not the most important. The most important is to win, to stay in the tournament, to try to get as far as possible, for sure try to raise your level when the opponents go stronger and stronger.

"Finally you're going to play somebody who has a Grand Slam or something like this."

Daniil Medvedev says he is not feeling the "extra pressure" of being the defending US Open champion after easing to a 6-2 6-4 6-0 victory over Stefan Kozlov in the first round.

The Russian won the first grand slam title of his career last year when he defeated Novak Djokovic at Flushing Meadows, and started his defence in dominant fashion on Arthur Ashe Stadium on Monday.

The world number one broke American outsider Kozlov eight times in a one-sided encounter in New York, in which he struck 37 winners and committed 19 unforced errors 

Top seed Medvedev does not feel burdened by being the man who won the final major of the year in 2021.

"[There is] a little bit [of] extra pressure [in being the defending champion]," he stated, "But mostly, I don't feel it, to be honest.

"Probably the only pressure is I know if I'm not going to play good here, for whatever reason... I will not care that I won it last year, I will just be disappointed that this year did not work out my way."

Medvedev will face Arthur Rinderknech next on Wednesday, after the Frenchman defeated his compatriot Quentin Halys in four sets on day one.

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.

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.