Top seed Iga Swiatek reached the US Open fourth round for the second time in her career after reeling off the final five games to beat Lauren Davis on Saturday.

The two-time French Open champion, who enjoyed a 37-match winning streak earlier this year, defeated Davis 6-3 6-4 in one hour and 57 minutes.

Swiatek had trailed 3-0 in the second lap but fought back emphatically to seal her passage into the last 16 where she will face either Jule Niemeier or Zheng Qinwen.

The attention in the women's singles has firmly turned to Swiatek, with Serena Williams eliminated along with the second, third and fourth seeds.

The Pole did not disappoint, hitting 25 winners and six aces, albeit with 38 unforced errors and an apparent lack of rhythm.

Swiatek wrapped up the first set in 59 minutes but world number 105 Davis offered a tougher test in the second after breaking in the second game.

The highly favoured Swiatek had to work out to avoid a 4-0 deficit, holding her serve in a 16-point game, but she showed she was back breaking Davis to love to make it 3-4.

Swiatek won 21 of the last 25 points of the match to book her spot in the second week in New York for the second straight year.

Data Slam: Swiatek finding her hard-court groove

The win improved Swiatek's 2022 tally to 53 matches but it also moved her a step closer to becoming the first player since Serena Williams in 2014 to win seven titles in a single year.

Swiatek has not quite reached the same dizzying levels lately since her 37-match winning streak, which was halted in the third round at Wimbledon, with this victory being only her fifth from eight during the hard-court season.

WINNERS/UNFORCED ERRORS

Swiatek – 25/38
Davis – 12/34

ACES/DOUBLE FAULTS

Swiatek – 6/3
Davis – 0/6

BREAK POINTS WON

Swiatek – 3/14
Davis – 1/3

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.

Ajla Tomljanovic explained she just had to block out the noise surrounding Serena Williams in order to progress at the US Open.

Williams' called time on her illustrious career following Friday's 7-5 6-7 (4-7) 6-1 loss to Tomljanovic, though did leave the door open to a possible return.

The 40-year-old had announced her impending retirement last month in Vogue, and before each of the three matches she played at Flushing Meadows, the tournament organisers paid tribute to the 23-time grand slam champion.

Williams had the backing of the crowd against Tomljanovic, who knew she had to cut through the background noise and focus on her game.

"I'd say the biggest thing was just to block out all the noise. At the end of the day I tried to keep it simple," she said.

"It's just another tennis match for me. I'm happy to be in the third round and have a great opportunity to play on Arthur Ashe. It's what I dreamed of when I was a kid. Just not make it bigger than it is because everyone else already made it huge.

"From the first moment I walked on court, I didn't really look around much. I was completely in my own little bubble."

Tomljanovic will face Ludmilla Samsonova in the next round and is already putting her win over Williams to one side.

"It's already kind of in the past. I mean, I'm happy I won, I actually think a little too quickly about the next one! I never feel like I have a problem with that. I have more of an issue chilling out and taking it easy the next day," she said.

Williams did not bow out without a fight, saving five match points in the deciding set before finally falling short.

"I stopped counting after the second [match point]," Tomljanovic said. "You know what, every match point she saved, it was all credit to her. I didn't feel like I did much wrong.

"I had this weird calmness because I felt like if I get broken, I mean, so what? Serena broke me. Wow, I'm just like the next person she broke when she's down 5-1.

"I know she comes up with her best tennis when she's in the most trouble. I didn't feel like I'm choking it away or something. I just kept calm and actually took a page of her book."

Ajla Tomljanovic had conflicting emotions after beating Serena Williams, as she admitted she felt like a "villain".

Williams' called time on her illustrious career following Friday's 7-5 6-7 (4-7) 6-1 loss to the Australian, though did leave the door open to a possible return.

The 23-time grand slam champion did not let it go easy, clawing back five match points before Tomljanovic finally clinched the deciding set.

While Tomljanovic is sad to see Williams go, she could not say she was sad to have won, sealing a place for herself in tennis history in the process.

"No one's going to pronounce my name right," she quipped after it was suggested she would now be the answer to a common trivia question regarding Williams' final opponent.

"That's going to suck. I don't think I've of been part of tennis history [before], so that's pretty cool.

"I do feel a little bit like the villain. Like I said in Cincinnati, I really did want to play Serena before she retired. If I was the loser today I'd probably be really sad. I don't want to say I'm sad, but just conflicted.

"Probably the most conflicted I've ever felt after a win. During the match I was so eager to win. I mean, I wanted to win as much as the next person because I didn't look at her like, 'oh, Serena, her last tournament'. 

"But then when it ended, it almost didn't feel right. When she started talking about her family and everything, I got emotional because I can relate to having a strong bond with your family.

"When she said that she wouldn't be there if it wasn't for them, I relate to that a lot. Just the whole moment after was just tough to handle a little bit."

Asked what Williams meant to her, Tomljanovic replied: "Growing up I didn't really have idols, but Serena and Venus [Williams] were just so good that I looked up to them the most, I'd say.

"What always drew me to them was their bond with their family, like the togetherness. They always spoke about that, like it was so important to them. I can relate to that because I'm very close to my family and I wouldn't be where I am without them.

"From a young age I remember seeing them with their dad and thinking that's kind of like my story a little bit. Just the fact that you don't have to have anything other than supportive family, a dream, and just will and passion and love for the game to make it. Not just make it, but what she's achieved is absolutely incredible.

"I don't know if it's ever going to be repeated while I'm still around. I still have years left in me. I want to dream bigger than I have so far because that's what she embodies."

Williams bows out with the most grand slam titles in the Open Era, though one short of Margaret Court's all-time record of 24.

Tributes have poured in across the sporting world for Serena Williams following her apparent US Open swansong on Friday, though the 23-time grand slam winner has kept the door ajar on a shock return.

The American, widely considered one of the greatest sportspeople of all time, suggested she would step away from top-level tennis following the tournament at Flushing Meadows.

Following a 7-5 6-7 (4-7) 6-1 loss to Australia's Ajla Tomljanovic in the third round, her journey now looks to be over – though the 40-year-old admittted "you never know" when asked about future appearances.

Her likely last dance, however, has prompted an outpouring of glowing tributes from far and wide, with a host of major names paying their respects to an unparalleld career.

15-time major-winning golfer Tiger Woods called her "the greatest on and off the court" while four-time NBA champion LeBron James hailed her as "so dope".

Serena Williams' long and illustrious tennis career looks to have drawn to a close after the American lost to Ajla Tomljanovic at the US Open on Friday. 

Following a long piece in Vogue last month, Williams wrote of her plan to "move in a different direction" after "these next few weeks", suggesting the tournament at Flushing Meadows would be her last outing.

Thanks to her success and brilliance on the court, Williams has become synonymous with tennis and is regarded by many as the greatest the women's sport has ever seen.

At the age of 40, Williams has persisted with tennis far longer than most do, and that is testament to her quality and enduring desire for success.

Though Williams left a glimmer of a chance that she may yet play again, joking that she "always did love Australia", she may well have taken to the court for the last time. Here, Stats Perform takes a look at the key facts, stats and figures of her career; in other words, Serena's remarkable legacy.

Twenty-three… and done?

Of course, the headline fact for Williams' career is her grand slam titles count.

She has won 23, which is more than anyone else in the Open era.

But she still had one target left: matching Margaret Court. The Australian's 24 grand slam successes include nine won before the Open era began in 1968, though her overall total has been the benchmark ever since she claimed her final crown at the US Open in 1975.

Clearly, victory for Williams at Flushing Meadows would have been the perfect farewell, but it was not to be. Will that near-miss encourage her to take one more shot in Court's homeland next year?

The finals hurdle

Had Williams managed to reach the championship match in Queens, she would have equalled another record.

She headed into the US Open having played in 33 grand slam finals, one more than Martina Navratilova.

But Chris Evert (34) sits out in front, and that record is now set to remain hers for many, many years.

Top of the pile

It's been a while now since Williams was last the highest-ranked player in the world, but in a way that only further highlights how remarkable her career has been.

She's spent 319 weeks ranked as world number one, which is behind only Steffi Graf (377) and Navratilova (332).

While many might have expected Williams to have been top of the pile for even longer, it's worth remembering how she's spent time out due to injuries and pregnancy, with her general involvement in top-level tennis decreasing after 2014 when she played 16 tournaments – in 2016 that halved to eight, and during no year since has she played in more.

Additionally, some will also be surprised to learn she actually only finished the year as the top-ranked female player five times. Nevertheless, that's still third to only Graf (eight) and Navratilova (seven).

Go hard or go home

Such has been Williams' quality, she was always considered a threat regardless of the surface – she's won each grand slam at least three times.

But there's no denying she was at her most lethal on hard courts.

She has won 48 WTA Tour-level titles on hard courts, which is 11 more than anyone else (Graf) in the Open era.

Those 48 come from a grand total of 73 across all surfaces, leaving her ranked fifth behind Navratilova (167), Evert (157), Graf (107) and Court (92).

Surface to say…

Williams' comfort on hard courts goes even further than that.

She's won 541 matches on the surface, making her one of just two female players to surpass 500 victories on one specific ground type.

Navratilova (600 on carpet) is the only other player to achieve the feat, with Serena's sister Venus (498 on hard) the closest to the 23-time grand slam champion.

The grass is greener

Despite that unrivalled excellence, hard courts may not be the surface many feel to be most synonymous with Williams, however.

Wimbledon is the tournament that would appear to be her favourite.

She's reached the final at SW19 11 times. Only Navratilova can better that record for the most finals at one tournament – though it's worth saying she contested the WTA Finals and Chicago 14 times each, Eastbourne 13 times and 12 at Wimbledon.

Serena Williams' long and illustrious tennis career looks to have drawn to a close after the American lost to Ajla Tomljanovic at the US Open on Friday. 

Following a long piece in Vogue last month, Williams wrote of her plan to "move in a different direction" after "these next few weeks", suggesting the tournament at Flushing Meadows would be her last outing.

Thanks to her success and brilliance on the court, Williams has become synonymous with tennis and is regarded by many as the greatest the women's sport has ever seen.

At the age of 40, Williams has persisted with tennis far longer than most do, and that is testament to her quality and enduring desire for success.

Though Williams left a glimmer of a chance that she may yet play again, joking that she "always did love Australia", she may well have taken to the court for the last time. Here, Stats Perform takes a look at the key facts, stats and figures of her career; in other words, Serena's remarkable legacy.

Twenty-three… and done?

Of course, the headline fact for Williams' career is her grand slam titles count.

She has won 23, which is more than anyone else in the Open era.

But she still had one target left: matching Margaret Court. The Australian's 24 grand slam successes include nine won before the Open era began in 1968, though her overall total has been the benchmark ever since she claimed her final crown at the US Open in 1975.

Clearly, victory for Williams at Flushing Meadows would have been the perfect farewell, but it was not to be. Will that near-miss encourage her to take one more shot in Court's homeland next year?

The finals hurdle

Had Williams managed to reach the championship match in Queens, she would have equalled another record.

She headed into the US Open having played in 33 grand slam finals, one more than Martina Navratilova.

But Chris Evert (34) sits out in front, and that record is now set to remain hers for many, many years.

Top of the pile

It's been a while now since Williams was last the highest-ranked player in the world, but in a way that only further highlights how remarkable her career has been.

She's spent 319 weeks ranked as world number one, which is behind only Steffi Graf (377) and Navratilova (332).

While many might have expected Williams to have been top of the pile for even longer, it's worth remembering how she's spent time out due to injuries and pregnancy, with her general involvement in top-level tennis decreasing after 2014 when she played 16 tournaments – in 2016 that halved to eight, and during no year since has she played in more.

Additionally, some will also be surprised to learn she actually only finished the year as the top-ranked female player five times. Nevertheless, that's still third to only Graf (eight) and Navratilova (seven).

Go hard or go home

Such has been Williams' quality, she was always considered a threat regardless of the surface – she's won each grand slam at least three times.

But there's no denying she was at her most lethal on hard courts.

She has won 48 WTA Tour-level titles on hard courts, which is 11 more than anyone else (Graf) in the Open era.

Those 48 come from a grand total of 73 across all surfaces, leaving her ranked fifth behind Navratilova (167), Evert (157), Graf (107) and Court (92).

Surface to say…

Williams' comfort on hard courts goes even further than that.

She's won 541 matches on the surface, making her one of just two female players to surpass 500 victories on one specific ground type.

Navratilova (600 on carpet) is the only other player to achieve the feat, with Serena's sister Venus (498 on hard) the closest to the 23-time grand slam champion.

The grass is greener

Despite that unrivalled excellence, hard courts may not be the surface many feel to be most synonymous with Williams, however.

Wimbledon is the tournament that would appear to be her favourite.

She's reached the final at SW19 11 times. Only Navratilova can better that record for the most finals at one tournament – though it's worth saying she contested the WTA Finals and Chicago 14 times each, Eastbourne 13 times and 12 at Wimbledon.

Serena Williams hinted that she will return to the court at some point in the future after going down in the third round of the US Open against Ajla Tomljanovic on Friday.

Williams, who saved five match points before eventually succumbing in the three-plus hour marathon, gave an emotional on-court interview where she thanked her family, but also highlighted that she felt like she was getting better as the tournament wore on.

When asked conclusively if this was her final US Open, she was non-committal, saying "you never know".

She took the insinuation that she is not finished playing a step further during her sit-down press conference, laying the breadcrumbs for another go around at the Australian Open.

"I don't know [what it would take to play again] – I'm not thinking about that. I always did love Australia, though," she said with a smile.

"But yeah, you know what, I've come a long way since last year at Wimbledon. Just not sure if that was my last moment or not. Making it a different moment I think is much better.

"And it takes a lot of work to get here. Clearly I'm still capable. It takes a lot more than that. 

"I'm ready to, like, be a mom, explore a different version of Serena. Technically in the world I'm still super young, so I want to have a little bit of a life while I'm still walking."

When asked what she thinks her life will be like moving forward, Williams said she is excited to be able to spend more time with her daughter, and that karaoke is on the agenda.

"I'm definitely resting tomorrow, and then probably spending some time with my daughter," she said. "I'm a super hands-on mom. I've been with her almost every single day of her life, minus two days or three days.

"It's been really hard on her, my career. So it will be, you know, nice just to do that and spend some time with her, do things that I never really have done or had an opportunity to do. I have such a bright future ahead of me, I don't know.

"Also, I'm kind of at an advantage because COVID happened. I think everyone shut down for a year, and we kind of got to see what our lives would be like if we weren't playing tennis. 

"Then I got injured last year, so I took off literally a year. So I got to see, again, like, what every day would be like to wake up and not have to go to the gym.

"So I don't know. I think I'm definitely probably going to be karaoke-ing tomorrow."

Touching on how she would like her career to be remembered, Williams said her unique passion and fire is at the forefront.

"I mean, there's so many things to be remembered by," she said. "Like the fight. I'm such a fighter. 

"I feel like I really brought something, and bring something, to tennis. The different looks, the fist pumps, the just crazy intensity. I think that obviously the passion, I think, is a really good word.

"Just continuing through ups and downs. I could go on and on. But I just honestly am so grateful that I had this moment, and that I'm Serena."

Serena Williams was emotional during her post-match interview in the sold-out Arthur Ashe Stadium after her loss to Ajla Tomljanovic in the third round, thanking her family for their decades of support.

Williams ended up going down in a match that lasted three hours and seven minutes, with a 15-minute final game where Williams saved five match points illustrating her fighting spirit down to the last moments.

If this is her final US Open – which she was hesitant to confirm – she will finish with the most main draw wins ever at the tournament with 108, and her 23 grand slam titles are also the most of all-time.

Speaking on the court after Tomljanovic gladly ceded the floor to the legend, Williams turned her attention immediately to her family as she reflected on the journey to this point.

"Thank you, Daddy. I know you're watching," she said as she began to tear up. "Thanks, Mom… I thank everyone that's here, that's been on my side so many years, decades. Oh, my gosh, literally decades.

"But it all started with my parents – they deserve everything. So I'm really grateful for them. These are happy tears, I guess. I don't know.

"And I wouldn't be Serena if there wasn't Venus, so thank you, Venus. She's the only reason that Serena Williams ever existed."

She added: "It's been a fun ride. It's been the most incredible ride and journey I've ever been on, I mean, in my life.

"I'm just so grateful to every single person that's ever said 'go, Serena' in their life. I'm just so grateful."

When asked if this would definitely be her last US Open, Williams was hesitant due to how well she performed, and left the question unanswered.

"I mean, I'm literally playing my way into this and getting better – I should have started sooner this year," she said with a laugh.

"I don't think so, but you never know. I don't know."

Serena Williams' last US Open has come to an end in the third round, going down 7-5 6-7 (4-7) 6-1 against Ajla Tomlanovic on Friday night.

It was a rough start for Williams, getting her serve broken in the first game of the match, but she got it straight back with a break-to-love by utilising her stunning power.

While her power brought her some easy points, it was also her undoing at times, with 16 unforced errors in the first set compared to 10 winners.

After securing another break to go up 5-3, serving for the opening set, Williams could not finish it off, losing the next four games in a row as Tomljanovic found a way to extend points and turn them into grinding rallies.

Not disheartened, Williams came out on fire in the second set, ripping off the first four games, but Tomljanovic again fought back. From 5-2 down, the Australian surged to level things at 5-5 before forcing a tiebreaker.

In the tiebreaker, Williams worked her way to a 5-4 lead, and took two consecutive mini-breaks to send the crowd into raptures and the match to a deciding set.

But where world number two Anett Kontaveit folded in Williams' last match, Tomljanovic did not, responding instantly after having her serve broken in the opening game to take the next five in a row, with a chance to serve things out at 5-1.

The crowd tried to will the living legend back into the contest, saving the first five of Tomljanovic's match points as she refused to go down easily, but she was not able to convert either of her three break point opportunities in a final game that lasted nearly 15 minutes, ultimately going down on the sixth match point.

After a collective groan in the sold-out Arthur Ashe Stadium, the crowd rose to their feet to pay their respect to the greatest women's tennis player of all time in her final outing at the US Open, as she treated the crowd to one more of her famous twirls at the grand slam she has won six times.

Data Slam: Six-time champion Serena leaves behind records that will stand the test of time

Williams finishes her US Open career with the seven more main draw wins than any other player, male or female. Her 108 wins leads Chris Evert (101), Jimmy Connors (98), Martina Navrilova (89) and Roger Federer (89).

She is also one of five players – along with Navrilova, Federer, Rafael Nadal and Novak Djokovic – to spend at least 300 weeks as the world number one, and her 23 career grand slam titles is the most of any player, leading Steffi Graf (22) and Nadal (22).

WINNERS/UNFORCED ERRORS

Williams – 49/51

Tomljanovic – 32/30

ACES/DOUBLE FAULTS

Williams – 11/7

Tomljanovic – 3/9 

BREAK POINTS WON

Williams – 5/13

Tomljanovic – 8/13

Coco Gauff admitted it would be a "lifelong dream" to face Serena Williams at the US Open, in what is likely to be the latter's final tournament of a glittering career.

Gauff reached the second week at Flushing Meadows in the women's singles for the first time after cruising to a 6-2-6-3 win over Madison Keys on Friday.

The number 12 seed saw off her fellow American in composed fashion to book her place in the last 16, exceeding her previous best result at the US Open in 2019.

Gauff was largely in control against the number 20 seed Keys to deliver near-flawless performance, chasing a second grand slam final of the year after finishing as runner-up at the French Open to Iga Swiatek.

She will face China's Zhang Shuai in the next round, but when asked if she will watch Williams' match against Ajla Tomljanovic later in the day during her on-court interview, Gauff said she would, adding: "It's been amazing watching Serena's matches so far. I don't know when I'd be due to face her but that's the goal.

"It's been a lifelong dream of mine to do that. Five years ago yesterday I was watching Venus and Serena play here. It's crazy to be on this court now.

"I tried to flex to my friends that I had courtside seats, now I'm on the court!"

Should both remain in the tournament, Gauff and Williams would face each other in the semi-finals.

Gauff also paid tribute to Keys, and to the crowd at Arthur Ashe Stadium, saying: "[The win] means a lot to me... I missed my alarm and was so late. I was here until 9pm last night and lost a doubles match [with Jessica Pegula].

"Kudos to my team, they got me up for it.

"I wasn't sure how the crowd was going to go. We all love Madison... I'm good friends with her off the court, but having support here meant a lot."

Ons Jabeur has now made it to the second week in all four grand slams after her win over Shelby Rogers at the US Open.

Jabeur, the fifth seed at Flushing Meadows, had previously fallen short of making the second week in the season's final grand slam, having reached the third round in three successive years between 2019 and 2021.

But the Tunisian world number five ended that wait with a 4-6 6-4 6-3 defeat of American Rogers.

Jabeur reached the final at Wimbledon this year, her first appearance in a major showpiece match, but lost to Elena Rybakina.

She has made it to the fourth round of the grand slams six times, having managed quarter-final runs at Wimbledon (2021) and the Australian Open (2020).

Another US Open fourth-round debutant awaits Jabeur in the form of Veronika Kudermetova, who despatched Dalma Galfi 6-2 6-0. 

Kudermetova's victory took just 46 minutes, making it the shortest match of the tournament.

Serena and Venus Williams saw hopes of one last US Open glory run together scuppered by a Czech pair who apologised for knocking out the American superstars.

The Williams sisters lost 7-6 (7-5) 6-4 against Lucie Hradecka and Linda Noskova on Arthur Ashe Stadium, with the doubles match given top billing in the New York night session.

Such scheduling had previously been unheard of, but such is the attention being foisted on the sisters that first-round doubles encounter was the match everyone wanted to see, knowing it could well be the last time the siblings play as a team.

Serena has indicated, albeit couched in somewhat vague terms, that this US Open will be her farewell to tennis. Venus, now 42, may follow suit and also retire from the sport.

While 40-year-old Serena remains in the singles, having beaten world number two Anett Kontaveit in round two to set up a Friday night clash with Ajla Tomljanovic, the dream of one more Flushing Meadows doubles title is over.

It was Czech-out time for the duo who have won 14 grand slam doubles titles together, and Hradecka said sorry to the partisan crowd for spoiling the party.

"I'm still in shock that we won, because we were playing for the first time with each other and I think we did a very good job," Hradecka said.

"I'm so sorry for you that we beat them, but we are so happy that we did it."

Hradecka had been planning on playing with Indian Sania Mirza, but an injury for Mirza put paid to that idea, meaning a new partner was required.

Noskova, 17, answered the 37-year-old Hradecka's call, and enjoyed a night to remember.

"Playing against the Williams sisters is a special moment for everybody, anytime," Noskova said.

"I was really lucky I could play with my doubles partner and we could win and pull out a good fight."

It was the Williams' first doubles match at a grand slam since the 2018 French Open, and their first at the US Open since 2014, and although it was a tight contest the younger pair just had the edge.

Neither sister gave an on-court interview or a press conference after the match, with all eyes now turning towards Serena's singles campaign, and the possibility of that extending deep into the second week.

Tennis great Roger Federer has congratulated outgoing 23-time major winner Serena Williams on an "incredible career".

The 41-year-old Swiss revealed in a video message posted by the ATP Tour that he stayed up as a teenager to watch Williams' maiden US Open triumph in 1999 and lavished praise on her impact in the sport.

Williams, 40, last month announced her intention to evolve out of tennis after the US Open, where she has remarkably progressed to the third round following her upset win over second seed Anett Kontaveit on Thursday.

"I wanted to congratulate you for a most incredible career," 20-time grand slam champion Federer said.

"You know what you've achieved. I know what you've done. You know what it is, it just beyond incredible.

"I know it's probably with mixed feelings you're leaving this wonderful sport that has given you everything and more. I wish you all the best with your family."

Williams has won six US Open titles during her decorated playing career, including her maiden Flushing Meadows triumph in 1999.

"I think back at '99 at the US Open when you played Martina Hingis, I stayed up late to watch you battle it out as that was the beginning to your incredible career that you've had ever since," Federer said.

"I think the future is going to be wonderful for you. I'm sure it is. Please return to tennis. The tennis community and family will always welcome you with open arms and always be happy to see you again, so please return.

"For now enjoy this moment, enjoy the US Open, enjoy everything that's coming this next couple of weeks even though it might be hard for you.

"But I'm thinking of you and all my respect. I wish you all the very best for your future. Take care Serena."

Federer has not played professional tennis since Wimbledon last year, but has not retired and the former world number one is hoping for a return to action soon.

Serena Williams and sister Venus were unable to advance past the first round of the doubles at the US Open, going down 7-6 (7-5) 6-4 against Czech duo Lucie Hradecka and Linda Noskova on Thursday.

It was the Williams' first doubles match at a grand slam since the 2018 French Open, and their first at the US Open since 2014, less than 24 hours after Serena's stunning upset of world number two Anett Kontaveit.

Leading 5-4 in the first set, the sisters had two opportunities to break and secure the first set, but ultimately let them slip, before going down in a competitive tiebreaker.

They were far from outclassed, winning 48 per cent (49-of-102) of the points in the opening set, and 45 per cent (33-of-74) in the second.

After going down 3-0 in the second frame, instead of rolling over, the Williams sisters fought back, pulling it back to 4-4, but that would be their last stand before dropping the next two games and the match.

There was no on-court interview for the Americans, although 17-year-old Noskova called it "a special moment" and said "I was really lucky" for the opportunity to play against her heroes.

Serena will continue her singles campaign in the third round on Saturday night against unseeded Australian Ajla Tomljanovic.