Naomi Osaka's wait for a deep run into a grand slam rolls on after the former world number one was beaten by Karolina Muchova at the US Open.

Osaka, a two-time champion at Flushing Meadows, lost 6-3 7-6 (7-5) on Thursday.

She came up against a player in fine form in Muchova, with the Czech displaying the quality that saw her reach the semi-finals a year ago.

"I was just really trying to be focused," Muchova said.

"I know she's an amazing player and that I have to bring the A-game to have a chance. So I was just trying to be really focused on myself. I knew I had to serve well because her serve is really good. So I was just trying to be kind of locked in myself and focused out there."

"Then the energy and the big court and all that, it for sure helps me. I like that."

Osaka, meanwhile, suggested the nerves got to her on Arthur Ashe Stadium.

"I think during the pressure moments I got nervous," Osaka said, and I don't know if I just have to keep playing more matches and get used to that feeling, especially on a really big stage.

"Honestly, if I get past the disappointment, I feel pretty proud of myself to have gotten that many opportunities while still feeling like I could have played much better."

Data Debrief: Fifth time's the charm?

Muchova is one of nine players to have defeated five former world number ones at grand slam events.

However, out of those, she is the only active player yet to win a major or a WTA 1000 title. Will that change in New York?

Carlos Alcaraz suffered a shock defeat to Botic Van de Zandschulp at the US Open.

Alcaraz, the French Open and Wimbledon champion, had been tipped to win a third major of the year at Flushing Meadows.

However, the Spaniard's hopes of becoming just the third player to win the French Open, Wimbledon and US Open in the same season were dashed by unseeded Dutchman Van de Zandschulp in the second round.

Van de Zandschulp prevailed 6-1 7-5 6-4 to cause the tournament's first huge shock.

"I think my level stayed at the same point all the match," said Alcaraz, who had won his previous 15 grand slam matches.

"It wasn't enough to win the match or to give myself the chance to get into the match or try to give myself chances.

"I didn't feel well hitting the ball. I think I made a lot of mistakes. When I wanted to come back, it was too late.

"He didn't make a lot of mistakes that I thought he was going to do so I was confused a little bit. I didn't know how to manage that.

"I came here with not as much energy as I thought that I was going to come with. But I don't want to put that as an excuse."

Data Debrief: Dutch delight

This was Van de Zandschulp's second career win over a top-five opponent, as he became just the second Dutch player to achieve that feat at the US Open, while he is the first from his nation to defeat a top-three player since 1991. 

Indeed, Van de Zandschulp, who will face Jack Draper next, snapped a 43-match losing streak for Dutch players against ATP top 10 opponents at the majors.

Jannik Sinner continued his quest for US Open glory in impressive fashion by beating home hopeful Alex Michelsen in straight sets at Flushing Meadows. 

Sinner, who is aiming to secure a second grand slam of 2024, needed just an hour and 39 minutes to dispatch his American opponent, emerging a 6-4 6-0 6-2 victor.  

The world number one navigated a difficult opening set, seeing his opening game break evaporate immediately before a break point in the ninth game gave him the early advantage. 

Sinner would showcase his class in the second, dropping 11 points throughout the entirety of the set to go within touching distance of advancing to the third round. 

Michelsen would match his opponent for the opening games of the third set, but a break in the fifth game proved decisive, with Sinner able to cruise to victory from then on.

The Italian's triumph set up a meeting with Australian Christopher O'Connell after overcoming a scare against Italian qualifier Mattia Bellucci in four sets. 

Data Debrief: The Italian job

Sinner's triumph over Michelsen saw him achieve consecutive 50-win seasons at ATP level, becoming the first Italian in the Open Era to reach that number.

The world number one impressed on serve, winning 30 of his 37 first-serve points, while also hitting 23 winners compared to the American's 15. 

Coco Gauff breezed into the third round of the US Open with a straight sets defeat of Tatjana Maria on Wednesday.

The reigning champion at Flushing Meadows won 6-4 6-0, with the minimum of fuss, on Arthur Ashe Stadium.

Gauff, who is seeded third, needed just 80 minutes to get the job done against her German opponent, and a third-round tie against Elina Svitolina is next up.

The American won seven games in a row to close out the match, with her second-set bagel her fifth at a grand slam this year.

"It was a tricky match," Gauff said. "Overall I thought I did well the first set. I mean, it was close. I got out of those service games.

"Obviously could serve better, but off the ground and at the net there were some errors, but I think every time it was the right decision to make. It was just about execution."

Gauff has met Svitolina, a US Open semi-finalist in 2019, twice before, beating the Ukrainian in this year's Auckland Open final after suffering a defeat at the 2021 Australian Open.

Data Debrief: Nine straight for Coco

Gauff has now won nine straight matches at the US Open, making her the youngest player to do so since Maria Sharapova between 2006 and 2007.

Indeed, the 20-year-old has now won 59 grand slam matches, which trails only Sharapova (81) when it comes to players aged under 21.

Novak Djokovic said he "served awful" after progressing to the third round of the US Open.

Djokovic was being pushed hard by his Serbian compatriot Laslo Djere in Wednesday's headline clash at Flushing Meadows.

Indeed, the reigning champion needed two hours to take the first two sets, but Djere was eventually forced to retire through injury, handing Djokovic a 6-4 6-4 2-0 victory.

"It was a big fight, more than two hours for two sets," Djokovic said.

"I served awful and without the serve, you have to grind, you have to run."

The victory brought up Djokovic's 90th match win at the US Open, moving him one clear of Roger Federer, with only Jimmy Connors (98) ahead of the 37-year-old.

"It doesn't get bigger than this in terms of a tennis stage," said Djokovic, who will face Australia's Alexei Popyrin in the next round.

"The atmosphere is incredible and it's a great privilege to be able to play here again at my age."

Data Debrief: Djokovic stands alone

Djokovic is now the only male player in the Open Era to win at least 90 matches at each of the four grand slams.

This win also improved Djokovic's career record against Djere to 3-0. His overall record against fellow Serbians, meanwhile, stands at 30-5, while he has only lost once in 19 hard-court matches against his compatriots, going down to Janko Tipsarevic at the ATP Finals in 2011.

Aryna Sabalenka is taking inspiration from the next generation of tennis fans as she aims to win the US Open, after her third-round win over Lucia Bronzetti.

Sabalenka made light work of the Italian on Wednesday, winning 6-3 6-1 to seal her place in round three.

Last year's runner-up did not face a single break point and converted four of the eight she forced.

After her victory, Sabalenka welcomed a young girl from the crowd onto the court for a photo.

In her post-match interview, the Belarusian said: "That means a lot, it's something that keeps me going. To see the young generation being inspired by me - this is what it's all about. I'm a little bit in shock because this is such an inspiration for me."

There was no such luck for Wimbledon champion Barbora Krejcikova, who suffered a straight-sets loss to Elena-Gabriela Ruse.

Krejcikova has failed to progress beyond round two at the US Open since she reached the quarters in 2021.

Data Debrief: Hard court specialist Sabalenka

Sabalenka tussled with Iga Swiatek on the clay courts earlier this season, but the world number two is excellent on the hard surface too.

Among active players, Sabalenka (80.6%, 45-11) trails only Naomi Osaka (81%, 47-11) in terms of win percentage on hard courts at grand slam events.

Carlos Alcaraz insisted he is not thinking about Rafael Nadal's grand slam record following his triumph over Australian qualifier Li Tu at the US Open. 

Alcaraz was able to overcome a scrappy second set to win 6-2 4-6 6-3 6-1 at Flushing Meadows, serving eight aces and producing 50 winners to his opponents' 19. 

The Spaniard started strongly, finding himself a set and a break to the good before four double faults in the second allowed Tu a way back into the contest. 

However, the world number three would recover, dominating the third as he confirmed his progression to the next round with a love game in the final set. 

Alcaraz is aiming to become the third man in history after Rod Laver and Nadal to win the French Open, Wimbledon and the US Open in the same calendar year. 

"Well, after this interview I’m going to try to pretend I never heard that," Alcaraz told ESPN when asked about the statistic. 

"Obviously it would be a great achievement if I make it, but it is going to be difficult."

The Olympic silver medallist faces Botic van de Zandschulp in the next round after the Dutchman defeated Denis Shapovalov in straight sets. 

Data Debrief: Alcaraz continues grand slam winning streak

Alcaraz's triumph at Flushing Meadows was his 15th grand slam victory in a row, last losing in a major tournament against Alexander Zverev at the Australian Open quarter-finals. 

Among players to begin their career in the Open Era, only John McEnroe (69) has achieved 60 men's singles match wins at grand slam events in fewer matches than Alcaraz (70), following the latter's win over Tu.

Emma Raducanu is hoping lessons will be learned from her first round defeat to Sofia Kenin at the US Open. 

Raducanu, who won the tournament 2021, lost in three sets 1-6 6-3 4-6 to her American opponent at Flushing Meadows, reducing her to tears after the encounter. 

After being outplayed by Kenin in the opening set, the world number 72 responded in the second to take the match the distance in New York. 

However, despite serving four of her six aces during the contest in the final set, Kenin would prove too strong to secure an all-American encounter with Jessica Pegula in the round of 64.

"I feel down, I feel sad," an emotional Raducanu said. "Obviously, this is a tournament I really want to do well in. 

"I was maybe a bit slow starting. I would have preferred to probably play, a little bit more before coming into the US Open."

"You know, I know when I have a lot of matches, just like every player, you feel really good. You feel like everything's automatic.

"So yeah, I think I can learn from it. And you know my manage my schedule slightly differently."

Data Debrief: Raducanu loses the battle of former grand slam winners

Raducanu's match against Kenin is the second R128 match at this year's US Open between two former women’s singles grand slam winners.

And while not at her best, Kenin was able to showcase her resilience that won her the Australian Open in 2020, saving six of the nine break points she faced. 

Jannik Sinner survived an early scare in the US Open first round after overcoming Mackenzie McDonald on Tuesday.

The Italian managed a 2-6 6-2 6-1 6-2 victory over the world number 140, having looked well off the pace in the opening set.

McDonald's fellow American Alex Michelsen awaits in the second round for Sinner, who triumphed in his first major match since an independent tribunal cleared any wrongdoing from positive tests for banned substances.

The world number one may have been impacted by those ongoing off the court and was slow to get going, dropping his serve three times en route to a first-set concession.

Sinner held off seven break-point opportunities from the home favourite in that opener, and improved from then on, losing on his serve just once in the second set.

The 23-year-old never looked back from that second-set clincher, easing to victory in just under two-and-a-half hours.

Data Debrief: Super Sinner flying

Sinner, who won his maiden major trophy at the Australian Open in January, is now 49-5 for the season after an impressive 2024.

That run includes lifting a third ATP Masters 1000 crown in Cincinnati last week, where he overcame his next opponent Michelsen in the pair's only ATP Tour meeting to date.

Naomi Osaka secured a long-awaited victory over a top-10 opponent after dispatching Jelena Ostapenko at the US Open on Tuesday.

World number 88 Osaka scored a 6-3 6-2 victory against Ostapenko for her first top-10 win in four-and-a-half years.

Osaka has now won 23 of her 28 matches at the US Open, at an 82% win ratio, which only Bianca Andreescu (86%) can better among current players with 10 or more main-draw matches at the tournament.

The four-time major winner was reduced to tears after downing the 10th seed in New York.

"I was trying not to cry when I was walking out too," Osaka said in her on-court interview. "I remember last year I was watching Coco [Gauff] play and I so badly wanted to step on these courts again and I didn't know if I could.

"I didn't know athletically, physically if I was able to. Just to win this match and just to be in this atmosphere means so much to me, so thank you."

Osaka, who won 39 of her 50 service points and held her serve throughout, needed three match points to move into the second round.

"I mean it was stressful, she was hitting some really good shots and I just told myself like, keep going, keep fighting for every point and maybe you'll have an opportunity," she added. 

"Eventually I did but then I looked up and then I saw so many faces so I was like, woah."

The unseeded Karolina Muchova awaits on Thursday for the Japanese star after her first-round triumph.

Iga Swiatek moved into the US Open second round after holding off a spirited Kamilla Rakhimova for a straight-sets win on Tuesday.

Lucky loser Rakhimova came close to forcing a decider, but the world number one rallied to win 6-4 7-6 (8-6) in just under two hours.

The early stages of the match suggested it would be a one-sided rout as Swiatek got two early breaks to race into a 4-0 lead, but Rakhimova clawed it back to 4-3 before the Pole dug in to take the set.

A similar story followed in the second set, though the world number 104 was unable to close out the victory after edging in front at 5-4, with Swiatek forcing a tie-break.

Swiatek then saved a triple set point from 6-3 down, winning the final five points to avoid an early upset and set up a meeting with either Daria Saville or Ena Shibahara in the next round.

Data Debrief: Swiatek tries her luck

It could have been a much different story for Swiatek had Rakhimova been able to hold her nerve in the tie-break, but as such, the 2022 winner stays in the tournament.

She is now the fifth-youngest player in the Open Era to win the first round in 20 consecutive women's singles grand slam events.

Meanwhile, only Serena Williams (93) and Venus Williams (94) have made 80 women's singles grand slam wins in fewer matches than Swiatek (97) this century.

Aryna Sabalenka made light work of Priscilla Hon to kick-start her US Open campaign in confident fashion on Sunday.

Sabalenka, who reached the final last year before losing out to Coco Gauff, did not face one break point in the first set and recovered from an indifferent start to the second to stroll into the second round with a 6-3 6-3 victory.

The Belarusian has won the last 12 sets she has played following on from her victory at the Cincinnati Masters, and this was her 40th Tour-level win this year.

Sabalenka will face Italy's Lucia Bronzetti in the second round on Wednesday.

Data debrief: Sabalenka keeps up hard-court form

This was Sabalenka's 24th WTA-level victory on hard courts this year.

Only two players have recorded more victories on the surface in 2024 - Emma Navarro (26) and world number one Iga Swiatek (25).

Novak Djokovic was not at his best to start his US Open title defence, but still eased beyond Radu Albot in straight sets.

Djokovic, who is hunting his first grand slam title of the year on the back of claiming Olympic gold in Paris, won 6-2 6-2 6-4 on Sunday.

However, Djokovic was not at his best, making 40 unforced errors and 10 double faults.

"I wanted to kick start the tournament in the right way and I think I did," Djokovic told ESPN.

"Some ups and downs which I think is normal, getting the rust off your shoulders coming off a different surface and the Olympic Games.

"I haven't played on hard courts for six months, so I'm still finding that groove, finding the tempo on the court."

Next up for Djokovic, who would claim his 100th Tour-level title should he triumph in New York, is his compatriot Laslo Djere, who defeated Jan-Lennard Struff.

Data Debrief: Djokovic equals Federer

Only the great Jimmy Connors (98) has won more US Open singles matches than Djokovic, who claimed his 89th victory at Flushing Meadows to match Roger Federer's tally.

This was also Djokovic's 78th win at Arthur Ashe Stadium, a competition record for a male player.

Dominic Thiem's grand slam career ended in the first round of the US Open in a straight-sets defeat to Ben Shelton on Monday.

Thiem won his sole major at Flushing Meadows in 2020, coming from two sets down to beat Alexander Zverev with no crowd present due to the Covid-19 pandemic.

In what turned out to be his final appearance at a grand slam, Shelton cruised to a 6-4 6-2 6-2 victory, before the American led the crowd in a standing ovation for Thiem.

The Austrian has struggled with a wrist injury in recent years, and announced in May that he would be retiring at the end of the 2024 tour.

Thiem was the first Austrian player in the Open Era to receive a wildcard for the men's singles at the US Open, and the first to receive wildcards to multiple grand slam events after last year’s Australian Open

"It's actually a really important moment for me because I had my greatest success of my career here on this court, in a weird 2020 in very strange and different circumstances," Thiem told the crowd.

"I'm super happy that I got the chance to play my last US Open and I can spend some time with you guys, just to say thank you and to make the time up from what we missed four years ago."

Elsewhere, fourth seed Zverev, Andrey Rublev and 2022 finalist Casper Ruud were among the winners in the first round in New York.

Novak Djokovic is hoping his Olympics success will spur him to US Open glory despite not playing since the Paris Games.

Djokovic became just the second player in the Open Era to win all four grand slams, the gold medal at the Olympics and the ATP Tour Finals after Andre Agassi.

The Serb triumphed at Flushing Meadows last year, winning his 24th major title, but one year on, is still waiting for the win that would take him clear of Margaret Court as the outright record holder.

He came close at Wimbledon but lost the final in straight sets to Carlos Alcaraz, who he then beat to claim his elusive gold medal earlier this month.

Djokovic, the number two seed for the tournament, will begin against Moldovan qualifier Radu Albot on Monday, and he believes his recent success will serve as the perfect springboard for a similar outcome in New York.

"I hope to never recover from that [Olympic triumph] because it's the best set of feelings that I ever had as an athlete," he told Eurosport.

"On the court but also off, when we went back to celebrate with our people, all of the Serbian Olympians that managed to win a medal.

"It was a very unique moment for me. I'll never forget it, and I'll try to use it as a great confidence boost for what's coming up in New York in the next few weeks."

At 87.1%, Djokovic holds the second-best win percentage at the US Open in the Open Era of players to have featured in at least 30 matches at the event, after Sampras (88.8%).

And the 37-year-old will be hoping that is a good omen as he aims to win a joint-record fifth title at the tournament.

Alcaraz and Jannik Sinner have split the major trophies between them so far in 2024, while the last time Djokovic failed to win a single grand slam in a calendar year was in 2017.

Djokovic has not competed in the hard-court swing so far, instead choosing to recover, having struggled with a knee injury since the French Open in May, but he is sure that break will help his performance.

"I haven't had much time to recover or much time to train," he added. "I tried to get the most out of the few weeks that I had.

"I had more than all the other guys that played the tournaments, but that was a conscious decision that I made not to have any lead-up tournaments to the US Open because I just felt that the calendar is too congested this year with the Olympics.

"I needed my break, short but sweet, celebration, family quality time and then, of course, [I] started my training and trying to build my body, build my form for the start of the tournament."