History-chasing world number one Novak Djokovic cruised through to the third round of the US Open at the expense of Tallon Griekspoor 6-2 6-3 6-2.

Djokovic is bidding to become just the third man to complete a calendar Grand Slam and the first to sweep all four majors in a year since Rod Laver in 1969.

The top seed, who is also pursuing a record-breaking 21st slam crown – currently level with injured stars Rafael Nadal and Roger Federer on 20 – outclassed Griekspoor in one hour, 39 minutes on Thursday.

Awaiting Djokovic is 2014 US Open finalist and Japanese star Kei Nishikori in the third round.

Djokovic, who withstood a spirited challenge from Holger Rune in the opening round before the teenager succumbed to cramps, asserted his dominance against Griekspoor from the outset on Arthur Ashe Stadium.

Boasting a 14-0 record in second-round matches at the US Open, Djokovic only lost one point on his first serve in the opening set and fired down five aces, while hitting 13 winners and converting two of his three break points.

While world number 121 Griekspoor managed to break Djokovic's serve in the second set, the Serb was typically efficient as he builds towards another shot at history in New York.

Coming to the net more in the third set, Djokovic was determined to get off the court as quickly as possible and he did just that – saving three break points en route to another third-round appearance at the year's final slam.

Data slam: Djokovic continues strong record

The 34-year-old came into the contest with a 52-1 slam record against non-top 100 opponents. Djokovic improved to 53-1 – his lone loss to world number 117 Denis Istomin at the 2017 Australian Open – and a perfect 13-0 at the US Open with his straight-sets victory.

WINNERS/UNFORCED ERRORS

Djokovic – 33/20
Griekspoor – 20/28

ACES/DOUBLE FAULTS

Djokovic – 13/5 
Griekspoor – 5/2

BREAK POINTS WON

Djokovic – 6/10
Griekspoor – 1/4

World number one Ash Barty said her serving struggles are "not a concern" after advancing to the US Open third round.

Barty continued her quest for a third grand slam title and first US Open crown with a 6-1 7-5 win over teenage prodigy Clara Tauson on Thursday.

Reigning Wimbledon champion Barty hit 33 winners and fired down 11 aces to see off the 18-year-old on Arthur Ashe Stadium in New York.

Barty, though, had to stave off a late challenge just like the top seed did against Vera Zvonareva in the opening round.

After she faltered to serve out the match at 5-4 in the second set of her victory over Tauson, Barty said: "It's happened a few times, but I have won 40-odd matches [this year] and it hasn’t happened a lot.

"It's just a few of those games I haven't been able to get up and hit my spots on first serves.

"When you give good players looks at second serves, you're going to get hurt. It's simple as that. It’s not a concern."

Barty leads the WTA Tour this season for titles won (five), match victories (42), finals reached (six), aces (319) and top-10 wins (seven).

"There's room for improvement, without a doubt, but there's room for improvement every single day," said Barty, who has never reached the quarter-finals at Flushing Meadows.

"Credit to her, she was a little bit more aggressive in that second set. I got a little bit passive and just let my energy drop and allowed her back in.

"We'll go back and have a chat about the matches and, once we get back on the practice court, try and fix a few things up, trust myself and trying to continue to play how I want to play."

Next up for Australian star Barty is either 2020 US Open quarter-finalist Shelby Rogers or Sorana Cirstea.

The Brooklyn Nets have added another All-Star to the mix, agreeing to a deal with veteran forward Paul Millsap. 

Millsap's agent DeAngelo Simmons confirmed the move to The Athletic and other outlets, and the player posted an image of himself in a Brooklyn uniform on his Instagram page on Thursday. 

The 36-year-old Millsap is entering his 16th NBA season, spending the first seven years of his career with the Utah Jazz before four seasons each with the Atlanta Hawks and the Denver Nuggets.

His best years came in Atlanta, where he made the All-Star team all four seasons. 

Millsap's playing time steadily diminished in Denver last season as he lost his starting job and ended up averaging just 20.8 minutes and 9.0 points per game – his lowest since his second year in the league. 

At this stage of his career, Millsap will be a complementary player on a loaded Brooklyn team that also features Kevin Durant, James Harden, Kyrie Irving and Blake Griffin. 

He effectively steps into the role vacated by fellow veteran Jeff Green, who averaged 11 points in 27 minutes for Brooklyn last season before signing a two-year deal with the Nuggets last month. 

Joining the star-studded Nets squad gives Millsap a strong chance to make the NBA Finals for the first time in his career. He has been on teams that reached the conference finals three times, but his team never won more than one game in any of those series. 

Potentially finishing his career with a contender was a priority for Millsap, as The Athletic reports he also considered the Los Angeles Clippers, Golden State Warriors and Chicago Bulls. 

Alexander Zverev believes his comeback victory over Novak Djokovic at the Olympics has paved the way for his fine start at the US Open.

Zverev came from a set down to defeat world number one Djokovic 1-6 6-3 6-1 at the semi-final stage in Tokyo, with the German going on to claim gold by beating Karen Khachanov in straight sets.

The world number four carried the winning form to Cincinnati, triumphing at the Western and Southern Open, and has made a smooth start at Flushing Meadows, where he lost out to Dominic Thiem in last year's final.

Zverev did not offer up a single break point in a dominant first-round win over Sam Querrey, and lost only four games when cruising past Albert Ramos-Vinolas 6-1 6-0 6-3 on Thursday.

"The process started at the Olympics for me, and the match against Novak," Zverev told reporters.

"That kind of started it off, because I was down badly, and I managed to win with great tennis.

"It was very important for me to kind of back it up in Cincinnati, because a lot of the times players that for the first time in their career win something really big like a grand slam title or a gold medal, they do tend to go downhill a little bit.

"So it was important for me to go to Cincinnati, to a place where I have never won a match before this year, and have a great tournament."

Another motivation for Zverev is the cruel fashion in which he lost to Thiem last year, when he surrendered a two-set lead.

"I mean I was the first man in 785 years to lose a US Open from two sets to love up and being a break up in the third set, serving for it in the fifth set, being two points away multiple times, it was painful," Zverev said with a smile.

"I still remember it, I remember it every single time I walk on this board but I take it as motivation because I'm back here to hopefully play a great tournament and win a grand slam title, that's what I’m here to do."

Zverev has now tallied up 40 wins in 2021 and 13 on the bounce, though the 24-year-old - who could meet Djokovic in the semi-finals - knows he has to maintain his strong service game to keep his best tennis.

"My serve is kind of the key to my game. When it's working I'm playing great. When it's not, I'm losing matches like I did at Wimbledon," he said.

"It's no secret that my serve is probably the most important shot in my game, and I'm happy with how it's working. The matches are not going to get easier and I will need that to be my weapon.

"I think it was always a problem of mine at the beginning of my career that I always spent a lot of hours, a lot of time in the beginning of grand slam tournaments. So it's nice to have two matches, winning [them] in straight sets."

Miguel Angel Lopez sealed a first stage victory of the 2021 Vuelta a Espana for Movistar as Primoz Roglic came second to increase his lead in the general classification. 

The demanding 18th stage concluded with a 14.6-kilometre climb - and it was with roughly with four to go that Lopez made his move. 

With a group of the world's best riders not far behind and primed to take advantage should he ultimately come up short, the Colombian knew he would likely need to maintain his aggression all the way to the finish. 

And despite the chasing pack edging a little closer in the latter stages, Lopez did enough to cross the line up in the clouds at the summit finish on Altu d'El Gamoniteiru, ending up 14 seconds clear. 

Missing out on first place will have been of little concern for Roglic, however, as the two-time Vuelta winner added another few seconds to his overall advantage over Lopez's Movistar team-mate Enric Mas as he enjoyed a strong conclusion to the last major climb of the race. 

Despite finishing well, Roglic stressed just how difficult Thursday's outing was after a superb effort when winning stage 17, while he was happy to be done with the high mountains at the Vuelta for 2021. 

"It felt like a queen stage, it was really hard, especially after yesterday's effort," he said. "It was extremely hard for me and I'm happy that I had something left to climb this mountain. 

"We were off duty [with Bahrain Victorious and Movistar Team pulling the peloton]. In my opinion, we could have gone easier! It was a hard pace and a hard day from start to finish. 

"I'm happy we're done with the big mountains. We're all feeling the efforts from the last two days and the three weeks before. 

"Still there are hard stages to come. Hopefully, we can do our best and finish it off." 

STAGE RESULT

1. Miguel Angel Lopez (Movistar) 04:41:21
2. Primoz Roglic (Jumbo-Visma) +0:14
3. Enric Mas (Movistar) +0:20

CLASSIFICATION STANDINGS

General Classification

1. Primoz Roglic (Jumbo-Visma) 73:24:25
2. Enric Mas (Movistar) +2:30
3. Miguel Angel Lopez (Movistar) +2:53

Points Classification

1. Fabio Jakobsen (Deceuninck-Quick-Step) 250
2. Primoz Roglic (Jumbo-Visma) 162
3. Matteo Trentin (UAE-Team Emirates) 123

King of the Mountains

1. Michael Storer (Team DSM) 59
2. Romain Bardet (Team DSM) 54
3. Primoz Roglic (Jumbo-Visma) 48

What's next?

Friday's 191.2km route from Tapia to Monforte de Lemos could be decisive. Considered "hilly" rather than mountainous, the peloton is likely to be tired after the exploits of Thursday, meaning opportunities for breakaways should be presented.

Kimi Raikkonen says he "wouldn't change a single thing" about his Formula One career and does not expect to miss racing once he retires at the end of the season. 

The 2007 world champion announced on Wednesday that this will be his final campaign. 

Finn Raikkonen made his debut at the 2001 Australian Grand Prix and has gone on to start a record 341 races, winning 21 and finishing on the podium 103 times. 

The 41-year-old Alfa Romeo driver insists he will walk away with no regrets. 

Asked what his biggest strength as a driver is, he said: "I don't know if I have one! I had a good run, I'm happy with what I achieved. 

"Obviously you want to win and it's not easy to win. I wanted to win a championship, I got close quite a few times and managed to win it with Ferrari, so happy that it happened, especially with them. 

"But the rest, strength or not strength, I don't care. I had fun and I did it my way, and I wouldn't change a single thing even if I could, because otherwise then maybe we wouldn't be sitting here today if you changed one thing along the way. No complaints – I cannot really complain." 

Raikkonen has not thought about what comes next – and is certainly in no rush to commit to anything other than his family. 

He said: "No plans. I don't want to have some schedule put on, because obviously the last 18, 19 years in F1, since I started, I did rally in those two years [away from F1 in 2010 and 2011], there was always a schedule, always what is coming next and what is this date and that date. So I don't want that. 

"That's for sure one of the big reasons why I want to also do something else. Obviously, there's other schedules: family, the kids' schools and kindergartens and that stuff. 

"But I don't want the family life to be dictated by when is the next race or test or flight or next work. I'm not in a rush, and I've not even thought about it at all. 

"Obviously I've known this situation for quite a while, so there's always obviously opportunities to do this or do that, but right now I'm not interested to even think about it." 

He added: "Will I miss the racing? I don't know. I've done it so long that I doubt that I'll start to miss it that much." 

The US Open was mounting a clean-up and safety check operation on Thursday after being affected by a deadly storm that struck New York City. 

There would be no play before 12:00 local time (16:00 GMT), an hour later than matches usually get under way, and spectators were told they would not be allowed into the grounds until 11:00 at the earliest. 

Severe weather hit New York and New Jersey on Wednesday, with the tail-end of Hurricane Ida striking the area and causing at least nine deaths. 

Eight of those deaths recorded in New York resulted from basements flooding, the New York Post reported, with the flash flooding causing chaos in large parts of the city. At one point, 3.15 inches of rain fell in an hour, a record for the Big Apple. 

Tournament organisers were carrying out inspections to determine whether safety of visitors to the Flushing Meadows grounds could be assured. 

The US Open said in a statement: "We appreciate your patience as we evaluate the readiness of our site. The safety of our fans, players and staff is of the utmost importance. 

"We will be issuing an update to the schedule including gate opening and match start times. The current plan will not open gates before 11:00 am." 

The storms were so unusually powerful on Wednesday that the late-night match between Kevin Anderson and Diego Schwartzman on the covered Louis Armstrong Stadium was affected by rain, with water gusting in through openings despite the protection. 

It was moved to Arthur Ashe Stadium to be completed, with its original court left drenched. 

Transport in New York early on Thursday was proving problematic, with the Metropolitan Transportation Authority, responsible for the local bus and subway system, announcing an "extremely limited" service and urging customers to "stay home if you can". 

Ash Barty and Novak Djokovic, along with Olympic champions Alexander Zverev and Belinda Bencic, are among those due in action on Thursday. 

Max Verstappen believes George Russell will make life "very difficult" for Lewis Hamilton if he replaces Valtteri Bottas at Mercedes next year.

Williams driver Russell has been tipped to take Bottas' seat, with Silver Arrows boss Toto Wolff having revealed his desire to finalise his driver line-up for 2022 this month.

Russell stepped in for Hamilton at the Sakhir Grand Prix last year after the seven-time Formula One world champion tested positive for coronavirus.

The 23-year-old also conducted a Pirelli tyre test for Mercedes ahead of the mid-season break and Verstappen thinks his arrival would keep his fellow Brit Hamilton on his toes.

"If he joins then for sure he will make it very difficult for Lewis,” Verstappen, who trails Hamilton by three points in the battle for the title, said ahead of the Dutch Grand Prix this weekend.

"He jumped into the car in Bahrain and basically from lap one he was making it very difficult for Valtteri, so you can only imagine the more experience you gain in that car and the more you get accustomed within the team, naturally you're going to get faster.

"When you do your first race you're guided by the team about setup direction because you just don’t know what to do really, initially, with the car.

"I remember my first race at Red Bull, the thing I said was is that we will just follow a bit what Daniel [Ricciardo] is doing because I have no clue about what this car needs to go quick because even though F1 cars look pretty similar, the way of setting them up can be very different.

"I am very confident - already what you could see with the performance he did in Spa was really good.

"Of course, they set up the car a bit more for wet conditions but nevertheless to do that in a Williams was very impressive. I do expect him to do very well if he gets that seat."

Ferrari driver Charles Leclerc echoed Verstappen's sentiments.

“I have actually been team-mates with George for a year in karting and I think what I have seen of him since that time, is just that he is extremely talented," he said.

"Every time he gets into the car he's just quick straightaway, so his talent makes him special.

"If he goes to Mercedes next year, and I hope he does because I think he deserves a chance there, I'm pretty sure he will perform very, very well and impress more than one person."

Men's tennis would be a safe environment for any gay player ready to announce their sexuality, three of the brightest young talents in the game have said.

Speaking on the US Open's first Pride Day, Stefanos Tsitsipas, Daniil Medvedev and Felix Auger-Aliassime said players should not fear coming out.

A number of the best-known women's players of all time have been lesbian, including Martina Navratilova, Billie Jean King and Amelie Mauresmo.

However, there have been few modern-era 'out' gay stars on the men's ATP Tour, with Navratilova having said in the past that those that exist have been "so far in the closet I don't know who they are".

Russian world number two Medvedev said: "From my side, I think everybody would be super open if somebody would come out on the ATP Tour.

"The other question is: are there any gays on the ATP Tour? Again, until somebody comes out, you cannot know unless you're his best friend and you know what he goes through.

"I think it's great from the US Open, this initiative. I think the ATP honestly is doing a good job, also especially internally trying to provide info and to just make sure that if anybody wants to come out, he's gonna feel safe and secure.

"All the players would be happy for the guy if he does it."

Canadian rising star Auger-Aliassime, who like Medvedev and Tsitsipas has reached round three at Flushing Meadows, explained it was important for the tour to let players be themselves.

On the women's tour, Belgian players Alison van Uytvanck and Greet Minnen are engaged, while there are a number of other players from the LGBTQ (lesbian, gay, bisexual, transgender, queer/questioning) community.

But the men's tour in recent years has seen no such prominently out players, which world number 15 Auger-Aliassime finds surprising, given the high number of professionals.

"Recently I've started doing a survey inside the ATP about the LGBTQ+ community," Auger-Aliassime said.

"It's important these days to be aware of that and to be open-minded and the ATP needs to do that, in today's time it's needed.

"The reason we don't have openly gay players on the ATP Tour, I'm not sure of the reason, but I feel me, as a player, it would be very open, very welcome. Statistically there should be some, but for now there's not."

Tsitsipas was asked whether the tour would be a "safe space" now, for any player considering coming out.

"I think so. They would be supported, for sure," said the Greek world number three, speaking on Wednesday's Pride Day in New York.

"I don't know how it is in other sports. I see no reason, for example, a tour like the ATP not to accept something like this."

Sloane Stephens sent Coco Gauff spinning out of the US Open – then joined the clamour to stop toilet break "gamesmanship" in tennis.

In Wednesday's opening night match on Arthur Ashe Stadium, former champion Stephens took the fast route past world number 23 Gauff, speeding to a 6-4 6-2 victory.

Now ranked 66th, Stephens won at Flushing Meadows in 2017 and was tipped by Gauff to challenge for the title again this year. By beating Madison Keys and now Gauff, Stephens is showing she still has major game, and another former champion in Angelique Kerber could be her third-round opponent.

Gauff, now 17, has known Stephens for over seven years, having attended the now 28-year-old's 21st birthday party.

But the American pair put friendship to one side for their showdown, with Gauff, who had been fancied by many to go deep this fortnight, having her threat stifled by an in-form Stephens.

"I think the last time we hit, she was probably like 12. It was a little bit different," Stephens said afterwards.

"It's just been really nice to see her game kind of evolve and the things that she's doing, like how she's able to turn so much defense into offense and kind of do those movements. She is great at the net. She has a really great all-around game. It's been really nice to see.

"She's different from a lot of the up-and-coming players we're seeing now that are just super hard hitting, not much variety. She has a lot of variety. I think a lot of the younger girls, there's half that are very hard hitting and half that have a lot of variety. I think she's in the bucket with a lot of variety."

Gauff was asked whether Stephens could now be considered a title contender and replied: "Yeah, definitely. Today she was playing well. I knew these last couple of tournaments she's been playing better and better. I hope that she can make it all the way to the end.

"Obviously if you are going to lose, you want to lose to the champion. I think that I feel like I've learned that I'm capable of making it far in slams. I think if I tighten up a few things, that I'm capable of winning one."

The debate over toilet breaks in tennis was sparked by Andy Murray being furious with Stefanos Tsitsipas for spending eight minutes in the bathroom before tackling the Scot in the deciding set of their first-round match.

Murray, frustrated to be left waiting for his opponent to reappear, followed up his Monday night fury with a tweet that charged Tsitsipas with taking twice as long to visit the toilet as Amazon mogul Jeff Bezos took to travel into space.

There was no such spat in Stephens' quickfire win over Gauff, but the rules on spending a penny have been the currency of many a news conference this week.

"I honestly just thought Andy's tweet was really funny," said Stephens. "I didn't see exactly what happened. I'm not sure. I just thought it was hilarious. We all are like huge Andy fans. We love him.

"I can't speak for what happened in that match, but I do know on the girl's side, there still is a lot of that. It's gamesmanship.

"I think there definitely needs to be a rule or changes. They make a lot of rule changes for smaller things, like they took one minute off the warm-up. If someone goes to the bathroom for nine minutes, no one says anything.

"Six, eight minutes is a long time to leave a match. That changes the whole momentum of a match. If you're changing your clothes, what are you changing? What are you doing in there?

"When you get into six, seven, eight, nine minutes, okay, what are you doing in there? Do you need help? I can come help you. Like, what's happening? I think that's more where the issues are because it just becomes pure gamesmanship."

Gerrit Cole helped end the New York Yankees' four-game skid with 15 strikeouts in a 4-1 victory over the Los Angeles Angels in the MLB on Wednesday.

Cole struck out Angels two-way star Shohei Ohtani three times in a commanding display across seven innings on the hill, allowing only four hits.

The Yankees pitcher's 15 strikeouts are tied for the second most in a game without a walk in Yankees history. It was Cole's fifth game with 12 or more strikeouts this season.

Cole becomes only the third player this season to have 15 Ks in a game after Corbin Burnes on August 11 against the Chicago Cubs and Jacob de Grom on April 23 against the Washington Nationals.

The 30-year-old right-hander's starring display came at a crucial time for the Yankees who had won 13 straight before their four-game skid, which he ended in the final game of their nine-game road trip.

Leading 3-1 in the eighth inning, Aaron Judge homered for the 30th time this season to seal the win.

Yankees general manager Aaron Boone said: "He’s obviously had some really good ones in his career and certainly with us the last two seasons. That for me was up there. That was a guy in control, I felt like a step ahead of those guys all day."

Rays' hot streak halted by Red Sox

The Tampa Bay Rays' nine-game winning streak was halted by the Boston Red Sox 3-2 despite rookie Wander Franco continuing his on-base run, with the result having implications in the wildcard race.

Franco delivered a two-run homer from Chris Sale to put the Rays 2-1 up at the top of the third inning but the Red Sox replied with a Christian Vasquez's solo shot in the seventh to tie it up.

With Boston at bat in the ninth inning with two on, Jarren Duran hit into right field and Rafael Devers touched down to clinch the Red Sox win.

The win keeps the Red Sox (76-59) hot on the heels of the Yankees (77-56) but it also opens a gap on the Oakland Athletics (73-60) who lost 8-6 to the Detroit Tigers.

Miguel Cabrera homered for the Tigers before a crucial RBI when scores were tied at 6-6.

The Los Angeles Dodgers moved into top spot in the National League (NL) West for the first time in months as they secured a 4-3 win over the Atlanta Braves.

Max Scherzer tossed six scoreless innings with nine strikeouts before the Braves squared it 3-3, with AJ Pollock's low single allowing Justin Turner to get home for the go-ahead run in the eighth inning.

The San Francisco Giants suffered their fourth straight defeat, going down 5-2 to the Milwaukee Brewers, with the Dodgers jumping above them in the NL West.

The Seattle Mariners completed a shut-out of the Houston Astros to stay in the wildcard hunt with a 1-0 win.

Darvish's woes continue

San Diego Padres starting pitcher Yu Darvish had a tough time on the mound in his side's 8-3 loss to the lowly Arizona Diamondbacks. The Diamondbacks piled on six runs in the third inning as Darvish was pulled. The Padres pitcher allowed eight hits, one walk and five earned runs.

Edman's flying catch

St Louis Cardinals second baseman Tommy Edman went flying beyond the netting and into the front row of the stands as he took an amazing catch from Tyler Stephenson in his side's 12-2 loss to the Cincinnati Reds. Edman hustled 120 feet, leaping over the tarp, to make the catch.

Wednesday's results 

St Louis Cardinals 5-4 Cincinnati Reds
Colorado Rockies 9-5 Texas Rangers
Arizona Diamondbacks 8-3 San Diego Padres
Seattle Mariners 1-0 Houston Astros
Cincinnati Reds 12-2 St Louis Cardinals
Toronto Blue Jays 5-4 Baltimore Orioles
New York Yankees 4-1 Los Angeles Angels
Boston Red Sox 3-2 Tampa Bay Rays
Detroit Tigers 8-6 Oakland Athletics
Chicago White Sox 6-3 Pittsburgh Pirates
Cleveland Indians 5-3 Kansas City Royals
Chicago Cubs 3-0 Minnesota Twins
Milwaukee Brewers 5-2 San Francisco Giants 
Los Angeles Dodgers 4-3 Atlanta Braves

A's at Tigers

The wildcard permutations will continue to evolve when the Athletics take on the Tigers again to round out their three-game series.

Two-time major winner Victoria Azarenka says it is "bizarre" that fans need to be vaccinated to attend the US Open but not the players.

The 2021 US Open marks the first tennis tournament where fans must show their proof of COVID-19 vaccination in order to attend matches inside the Flushing Meadows venue. The decision was made less than 72 hours prior to the first matches at the US Open.

Azarenka, who defeated Italian Jasmine Paolini 6-3 7-6 (7-1) in the second round on Wednesday, said there was a double standard applied for fans compared to players who are not required to be vaccinated to play.

"I want to start this conversation between our players, because to me that's a bit bizarre that fans have to be vaccinated and players are not," three-time US Open finalist Azarenka told reporters.

"I think it's inevitable that it will be mandated at some point, like other leagues are doing.

"I don't see the point of stalling it, because I think we all want to be safe, we all want to continue doing our jobs, and I know there is a lot of discussions about it."

She added: "I hope that as an association we make the best decision for our business, for our health, for the tournaments and for the public."

On Saturday, Briton Andy Murray voiced his opinion that players need to be vaccinated, saying it is their responsibility as they travel the world to play.

Numerous top players including Novak Djokovic, Stefano Tsitsipas and Daniil Medvedev have previously spoken about their concerns about getting vaccinated.

Medvedev would not be drawn on Azarenka's comments after he defeated Dominik Koepfer 6-4 6-1 6-2 in the second round on Wednesday.

"Tough to answer this question," Medvedev told reporters. "I think everybody can have his own opinion.

"I understand why they did it to the fans. So far it has not been applied to the players. We as players, we can just follow the guidelines and the rules. That's all we can do.

"I think it's not for players to decide, because that's why we have governing bodies in tennis."

Stefanos Tsitsipas has defended his "personal need" for long bathroom breaks after being jeered during his four-set second round win over Adrian Mannarino at the US Open on Wednesday.

The world number three triumphed 6-3 6-4 6-7 (4-7) 6-0 but was booed by the Arthur Ashe Stadium crowd after taking a bathroom break which exceeded seven minutes.

The Greek was criticized by Andy Murray, who said he lost respect for Tsitsipas after taking a lengthy break ahead of the final set in their five-set first round epic on Monday.

Alexander Zverev weighed in on the discussion, claiming Tsitsipas was communicating with his coach during his bathroom breaks, labelling them "ridiculous" and saying he had broken an "unwritten law".

Tsitsipas reverted to the rule book in his defence after beating Mannarino, insisting he had done nothing illegal and longer breaks were part of his "personal needs".

"It's just my personal needs," Tsitsipas told reporters. "Some people have other needs. Some people take much more than 25 seconds between points, which is fair.  

"I've done everything the right way. If I haven't I should be penalized. I completely agree with it. I should get a fine or be penalized if I haven’t followed whatever I've done correctly. But as far as I know, it is a necessity, it is a need when I'm out there playing and performing."

Tsitsipas said he felt fans who booed and jeered did not understand the game or his need to take longer bathroom breaks.

"I haven’t done anything wrong so I don't understand," he said. "The people love the sport, they come to watch tennis. I have nothing against them. But some people don't understand. They haven't played tennis at high level to understand how much effort and how much difficult it is to do what we are doing."

He added: "It is important. First of all, you carry less weight on you with all the sweat. You feel rejuvenated, you feel fresh, and you don't have all the sweat bothering you and coming in your face, on your fingers, everywhere all over your body. It makes you feel better.

"For me it is important to take that break. For someone else probably not. And everyone has his own time. I try and be as quick as I can. Sometimes I just need a bit more time."

Tsitsipas added that he was taken aback by the public criticism from Murray and Zverev.

"I never complain of what other players do," the 23-year-old French Open runner-up said. "My parents have taught me not to watch other people's business and concentrate on myself. Do my job.

"I just don’t understand when some players go and criticize other players, or during a match they put too much emphasis on it."

There have been calls for a hard cap on the permitted time for bathroom breaks, which American Sloane Stephens agreed with, speaking after her straight-sets win over 21st seed Coco Cauff.

"I don't think you should be gone from the court for six-eight minutes," Stephens said. "It's a long time to leave a match. That changes the whole momentum of a match.

"I can't speak for what happened in that match, but I do know on the girls' side, there still is a lot of that. It's gamesmanship.

"I think there definitely needs to be a rule or changes. They make a lot of rule changes for smaller things, like they took one minute off the warmup. If someone goes to the bathroom for nine minutes, no one says anything."