Team Europe are poised to seal yet more Laver Cup glory after producing another dominant display against Team World, though the focus was on Nick Kyrgios following comments about his long-term future.

Europe swept Saturday's four matches in Boston to stand on the cusp of a fourth consecutive Laver Cup triumph – the defending champions lead 11-1 and require just two more points to clinch the title.

Stefanos Tsitsipas blitzed Team World's Kyrgios 6-3 6-4 at TD Garden, where Olympic Games gold medallist Alexander Zverev beat John Isner 7-6 (7-5) 6-7 (6-8) 10-5 before US Open champion Daniil Medvedev made light work of Denis Shapovalov 6-4 6-0.

Team Europe secured their fourth win of the day in the doubles – Tsitsipas and Andrey Rublev teaming up to defeat Isner and Kyrgios 6-7 (8-10) 6-3 10-4.

After Kyrgios' straight-sets loss to Greece's Tsitsipas, the 26-year-old Australian star casted doubt over his tennis future.

"This is my probably my last Laver Cup," former world number 13 Kyrgios – an Australian Open and Wimbledon quarter-finalist – told reporters post-match. "I don't know how much longer I will be in tennis.

"This is my last event of the year. I will get my body right ahead of the Australian Open.

"My mum is not doing too well with her health. I'd like to go back and see her."

"As long as I'm on the court, I will try and give my best, but I'm not going to lie and say that I'm going to plan to play four or five more years on tour," Kyrgios said. "That's just not me."

Playing for the first time since earning his maiden grand slam trophy at the expense of record-chasing Novak Djokovic at Flushing Meadows, world number two Medvedev suffered no letdown against Shapovalov.

"I played unbelievably, especially [in] the second set," Russia's Medvedev said in his on-court interview. "I didn't know what to expect because after the US Open, I didn't play for a week and a half. Came here, practised as much as I could the past three days, so I didn't hit [that] many balls, but was surprisingly feeling well.

"I wanted to show that also today. [The] first [set] was not easy, the ball was not going as fast as I wanted [and] he was playing really good. And then I just couldn't miss a ball anymore. I'm really happy about [that]."

Team Europe are on track for their fourth consecutive Laver Cup triumph after earning an early 3-1 lead against Team World.

Opening-day honours went to Bjorn Borg's Team Europe at TD Garden in Boston, where the defending champions moved into the box seat thanks to wins for Andrey Rublev, Matteo Berrettini and Casper Ruud in the singles on Friday.

John Isner and Denis Shapovalov managed to get Team World on the board in the evening's final doubles match against Alexander Zverev and Berrettini 4-6 7-6 (7-2) 10-1.

Roger Federer and Rod Laver were in the crowd as Team Europe – headlined by newly crowned US Open champion Daniil Medvedev and consisting of six of the world's top 10 – made a strong start courtesy of Norwegian Ruud, who overcame Reilly Opelka 6-3 7-6 (7-4), improving his career record to 3-0 against the towering American, and beating him in straight sets for the first time.

Italian star Berrettini then overcame Team World's Felix Auger-Aliassime 6-7 (3-7) 7-5 10-8 in the competition's longest match at two hours, 52 minutes.

Berrettini escaped with the second set after facing two break points in the penultimate game before prevailing against the Canadian in a thrilling match tie-break.

"One of the best matches bar none that I've ever seen played, absolutely just enthralling," said captain John McEnroe, whose Team World are eyeing their first Laver Cup trophy.

Rublev rallied past Argentina's Diego Schwartzman, who won the opening set and led 6-2 and 8-5 in the match tie-break before losing 4-6 6-3 11-9.

"Today we are a bit more lucky; Matteo won a tough match against Felix in a super tiebreak, now you saw my match," said Russian star Rublev.

"It was so close; Diego was leading all the super tiebreak, but in the end I find a way to win.

"This happens. This is tennis, this is sport. It’s emotions. Someone has to win, someone has to lose."

On day two, Stefanos Tsitsipas and Zverev headline the day session against Team World's Nick Kyrgios and Isner.

In the evening, Medvedev will meet Shapovalov before Rublev and Tsitsipas team up for a doubles battle with Kyrgios and Isner.

Hubert Hurkacz's fine season continued as he ended Andy Murray's run at the Moselle Open on Friday.

Top seed Hurkacz beat Daniil Medvedev and Roger Federer on the way to the semi-finals at Wimbledon, and previously beat Murray in Cincinnati.

Hurkacz is ranked 13th in the world and is pushing for a place at the ATP Tour Finals, and he edged closer to a fourth career title by defeating Murray again in Metz.

The 24-year-old prevailed 7-6 (7-4) 6-3 over the former world number one, who was playing in his first ATP Tour quarter-final of the year.

"Andy is an unbelievable competitor, he has achieved so much throughout his career," Hurkacz said. "He is coming back from a tough injury and playing at a very high level, so he is amazing and you can be inspired by his results."

Next up for Hurkacz is Peter Gojowczyk, who overcame Marcos Giron 3-6 6-1 6-3 and is backing up his recent US Open run in strong fashion.

The other last-four match will take place between French home favourite and third seed Gael Monfils, who has reached his first tour semi-final since February last year, and Pablo Carreno Busta.

Carreno Busta, the Spanish second seed, needed three sets to beat Holger Rune, while Monfils had an easier time of it against Nikoloz Basilashvili, winning 6-3 6-3.

At the Astana Open, second seed Alexander Bublik beat Carlos Taberner 6-3 6-4, as he hunts a first singles title.

A crowd favourite in Kazakhstan, whom he has represented since 2016, Russian-born Bublik faces a semi-final against Soonwoo Kwon, who got past Laslo Djere.

Fifth seed John Millman succumbed to fellow Australian James Duckworth, who will face Ilya Ivashka for a place in the final.

Anett Kontaveit beat Olympic champion Belinda Bencic and will face home favourite Petra Kvitova for a place in the Ostrava Open final.

Estonian Kontaveit, ranked 30th in the world, claimed her fourth top-20 win of the season as she prevailed 6-4 6-3 on Friday.

Kontaveit also defeated Bencic in the 2020 Australian Open, meaning she is 2-0 in their head-to-head rivalry.

Czech left-hander Kvitova awaits in the last four, after the second seed defeated Bencic's Swiss compatriot Jil Teichmann 6-4 6-4.

Teichmann beat Kvitova in their only previous meeting, but the world number 10 had too much on this occasion, along with the backing of the crowd to boot as she chases a 29th singles title of her career.

The other semi-final will see top seed Iga Swiatek face Maria Sakkari.

Last year's French Open winner Swiatek reached her first semi-final since May – when she landed the prestigious title in Rome – by overcoming Elena Rybakina 7-6 (7-5) 6-2.

Sakkari, meanwhile, ended Tereza Martincova's hopes in straight sets.

Greek star Sakkari ended Swiatek's reign as Roland Garros champion in June, beating the Polish 20-year-old in the quarter-finals in Paris.

US Open champion Emma Raducanu has split from coach Andrew Richardson and wants to partner with someone with greater WTA Tour experience. 

Richardson had coached Raducanu in her younger days at Bromley Tennis Centre and accompanied the 18-year-old for her campaign at Flushing Meadows. 

The experience proved unforgettable as the Briton, ranked 150 in the world at the time and having played in just one other major previously (Wimbledon in July), took the title after moving through qualifying and the main draw without dropping a set. 

She became the youngest grand slam finalist since Maria Sharapova won Wimbledon as a 17-year-old in 2004 and is the only qualifier in tennis history to win a major final. 

Her astonishing triumph catapulted her to 22 in the WTA rankings and Raducanu is now looking for someone to guide her through the next phase of her career. 

Speaking at a homecoming event organised by the Lawn Tennis Association, she said: "Where I was at after Wimbledon, I was ranked around 200 in the world and at the time I thought Andrew would be a great coach to trial, so we went to the States but never did I even dream of winning the US Open and having the run I did, and now I'm ranked 22 in the world, which is pretty crazy to me. 

"I feel like at this stage in my career, and playing the top players in the world, I realised I really need someone right now that has had that WTA Tour experience at the high levels, which means that I'm looking for someone who has been at that level and knows what it takes. 

"And especially right now because I'm so new to it, I really need someone to guide me who has already been through that. 

"Obviously having such an experience with your team, it's tough to have that conversation with anyone, but I think for me, it's just really what I need." 

It has been suggested Raducanu could look to partner with Darren Cahill, the renowned coach who split with Simona Halep this month. 

For now, she is considering when to make a competitive return to action, with the notable Indian Wells Open coming up. 

"I'll decide in the next few days where I'm going to go to but, wherever I play next, I'm going to make sure I'm ready. I don't want to jump into things too early," she said. 

Olympic gold medallist Belinda Bencic eased to a straight-sets win over Sara Sorribes Tormo to maintain her good form and book a place in the Ostrava Open quarter-finals.

Third seed Bencic needed just 88 minutes to see off her 36th-ranked opponent as she made it 15 victories from her past 18 matches.

Czech wildcard Tereza Martincova is also through to the last eight on home soil after battling past French Open finalist Anastasia Pavlyuchenkova 7-6 (7-5) 7-6 (8-6).

Martincova is into her fifth quarter-final of the season and will take on number four seed Maria Sakkari, who saw off Jelena Ostapenko 6-4 6-2 earlier on Thursday.

Also through to round three is Elena Rybakina following a hard-fought 6-3 2-6 6-1 win over qualifier Magda Linette, while Jil Teichmann – who shocked former world number one Angelique Kerber in the previous round – advanced in three sets against Alison Riske.

She will face Petra Kvitova for a place in the semi-finals. 

Top seed Aslan Karatsev exited the Astana Open at the last-16 stage with a straight-sets defeat to Emil Ruusuvuori on Thursday.

World number 84 Ruusuvuori saved a set point in the first-set tie-break on his way to a 7-6 (8-6) 6-4 victory and will now face Ilya Ivashka for a place in the semi-finals.

There was nearly another upset as home hopeful Alexander Bublik, seeded second, had to recover from a set down to overcome Miomir Kecmanovic 2-6 6-3 7-5.

Carlos Taberner awaits Bublik in the next round after the Spaniard beat Egor Gerasimov 5-7 7-6(5) 7-5.

Kwon Soon-woo and James Duckworth saw off Dusan Lajovic and Filip Krajinovic respectively in straight sets to remain a course for glory.

At the Moselle Open in Metz, meanwhile, Gael Monfils took out Philipp Kohlschreiber 7-6(2) 6-4 to reach the quarter-finals on home soil.

Tournament favourite Hubert Hurkacz made light work of 2016 champion Lucas Pouille with a 6-2 6-3 victory to set up a meeting with Andy Murray in the quarter-finals.

Elsewhere on Thursday, German qualifier Peter Gojowczyk proved too strong for Karen Khachanov and will now face Marcos Giron, who upset fourth seed Alex de Minaur.

Former world number one Naomi Osaka unsurprisingly withdrew from next month's Indian Wells Masters, having flagged a break from tennis following her US Open meltdown.

The tournament confirmed 2018 champion Osaka's absence on Wednesday, with the Indian Wells Masters scheduled to take place from October 4-17 after the 2020 edition was cancelled due to the coronavirus pandemic.

Osaka's US Open title defence came crashing down in a remarkable 5-7 7-6 (7-2) 6-4 third-round capitulation at the hands of eventual finalist Leylah Fernandez earlier this month.

Up a set and serving for the match at 6-5 on Arthur Ashe Stadium, four-time major champion Osaka lost her cool and composure after throwing her racquet three times in an unsuccessful second-set tie-break.

Amid boos in New York, Japanese star Osaka was also warned after hitting a ball into the crowd at Flushing Meadows.

After the surprise exit, Osaka told reporters she planned to "take a break from playing for a while."

She added: "I feel like for me recently, like, when I win I don't feel happy. I feel more like a relief. And then when I lose, I feel very sad. I don't think that's normal. I didn't really want to cry.

"I feel like… this is very hard to articulate. I feel like I'm kind of at this point where I'm trying to figure out what I want to do, and I honestly don't know when I'm going to play my next tennis match [tearing up]. Sorry."

It comes following a difficult couple of months due to mental health concerns as a result of "long bouts of depression" since winning the 2018 US Open.

Osaka withdrew from May's French Open having won her first-round match, after she was fined and threatened with further punishment – and possible expulsion from the grand slam – for skipping obligatory media duties.

She subsequently pulled out of Wimbledon before returning for the Olympic Games, though she suffered a surprise loss on home soil in Tokyo and was reduced to tears during a news conference in Cincinnati.

Andy Murray is building confidence after he claimed back-to-back wins for the first time since Wimbledon by defeating Vasek Pospisil at the Moselle Open.

Murray followed up Tuesday's triumph against Ugo Humbert with a straight-sets victory over the Canadian, reaching the quarter-finals with a 6-3 6-3 success.

The last eight will see Murray face either Lucas Pouille or top seed Hubert Hurkacz, who he lost to in Cincinnati last month.

However, Murray has since played an exceptional five-setter with Stefanos Tsitsipas at the US Open and the former world number one and three-time grand slam champion is feeling increasingly positive about his game.

"This period has been the most tournaments I've played [recently] and my body feels good and I'm starting to gain just a little bit of confidence with each match," Murray said in his on-court interview. 

"[I'm] starting to see the points and how I want to play them again, which is great. There have been times in the past year where I've been a little bit confused and not seeing how the points are developing and stuff, which for me was always a strong part of my game and it made me feel quite uncomfortable on the court when I was feeling that way.

"I'm starting to get that back and the results are coming and my tennis is getting better."

The two other last 16 matches saw second seed Pablo Carreno Busta defeat Mikael Ymer 7-5 6-2, while fifth seed Lorenzo Sonego fell victim to a comeback from teenager Holger Rune, who prevailed 6-7 (6-8) 6-4 6-4.

Pouille came from behind to set up his clash with Hurkacz with a three-set win over qualifier Brayden Schnur, and Peter Gojowczyk was victorious in another first-round match.

At the Astana Open, defending champion John Millman came through a marathon match with Jaume Munar to reach the quarter-finals. The Australian took victory 6-4 6-7 (5-7) 7-5 after three hours and nine minutes.

Seventh seed Laslo Djere needed three sets to see off Lorenzo Musetti but eighth seed Ilya Ivashka had little difficulty beating Timofey Skatov in straight sets.

There were also wins for James Duckworth, Kwon Soon-woo, Emil Ruusuvuori and Carlos Taberner.

Iga Swiatek coasted through to the quarter-finals of the Ostrava Open after defeating Yulia Putintseva as Paula Badosa faltered against Anett Kontaveit.

Favourite Swiatek provided an astute performance to ease past Putintseva 6-4 6-4 to secure a potential quarter-final tie with Elena Rybakina.

Petra Kvitova, who is second seed in Croatia, did not enjoy as comfortable a victory but battled past Anastasia Potapova 6-1 6-7 (4-7) 6-3 to confirm her last-eight berth.

The ninth ranked Badosa, however, was not as fortunate as she was dumped out by Kontaveit, who cruised to a 6-3 6-4 win over the world number 27 in just over an hour.

Jelena Ostapenko set up a last-16 clash with fourth seed Maria Sakkari as she defeated Anna Blinkova 6-4 6-0, while Alison Riske recovered from a second-set setback to defeat Fiona Ferro 6-4 1-6 6-4.

Riske will now meet Jil Teichmann, who shocked former world number one Angelique Kerber, and whoever wins will be rewarded with a tie against world number 10 Kvitova.

Simona Halep has confirmed she has parted company with her long-time coach Darren Cahill.

Halep, who was the year-end number one in 2017 and 2018, has been coached by Cahill for the past six years.

She won the 2018 French Open, her first grand slam title, under his guidance before Cahill left the team for a spell to spend more time with his family.

Cahill – who also guided Halep to the 2018 Australian Open final – returned to coach the Romanian ahead of the 2019 WTA Finals, following on from her success at Wimbledon.

The 29-year-old has endured an injury-hit 2021 and was knocked out of the US Open in the fourth round by Elina Svitolina.

In a post on her official Twitter account, Halep announced: "After six wonderful years working together, Darren Cahill and I have decided that it's time to end our working relationship.

"Thank you D for everything, for making me a better tennis player and a better person."

Former world number one Angelique Kerber was stunned by Jil Teichmann as she lost 6-2 6-3 in Tuesday's Ostrava Open first-round tie.

World number 42 Teichmann raced to a memorable victory against the three-time grand slam winner in just over an hour as the left-hand collected her sixth win against a top-20 player this season.

Half of those wins have come this year as well, with the Swiss beating Naomi Osaka, Belinda Bencic and Karolina Pliskova in a breakthrough Cincinnati campaign.

Fifth seed Anastasia Pavlyuchenkova cruised through after negotiating a difficult first set against Ana Konjuh to win 7-6 (7-3) 6-1 in just over an hour-and-a-half.

Tereza Martincova's victory over fellow Czech Katerina Siniakova did not come as easily, though, with the former edging to a 5-7 6-4 7-6 (9-7) win in more than a three-hour slog.

Martincova, who is ranked 61st in the world, miraculously recovered from 5-0 down in the tie-break to save a match point before securing her first main-draw win in Croatia.

Yulia Putintseva experienced similar difficulties against Shuai Zhang, as she also battled out in a three-hour marathon and saved a match point to eventually succeed 5-7 7-6 (9-7) 6-4.

Andy Murray battled through to the second round of the Moselle Open with a 4-6 6-3 6-2 victory over sixth seed Ugo Humbert on Tuesday.

Murray chose to play in the event as a wildcard to improve his world ranking and avoid tougher first-round encounters, such as facing Stefanos Tsitsipas at the U.S. Open, and he recovered from going behind in the opening set to ease through his first-round tie.

Humbert, who is ranked 26th in the world, came into the clash 87 places ahead of the two-time Wimbledon winner but failed to make home advantage count as the Scot dispatched of him in just over two hours.

Karen Khachanov, who is the seventh seed in Metz, avoided a similar first-set scare to overcome Alexandre Muller 4-6 6-1 6-3, while Marcos Giron edged past Arthur Rinderknech 3-6 7-6 (7-3) 6-4.

That win sets up a second-round tie with fourth seed Alex de Minaur, with Alejandro Davidovich Fokina sneaking past Gilles Simon 4-6 (4-7) 7-6 (7-2) 6-2 in Tuesday's other match.

Frenchman Benoit Paire crashed out of the Astana Open to world number 97 Egor Gerasimov as he lost 7-5 6-4.

John Millman, the fifth seed, did not endure similar struggles as he recovered from losing the first set to ease past Dmitry Popko 3-6 6-1 6-4.

Meanwhile, Ilya Ivashka coasted past Elias Ymer 6-2 6-4 in just over 90 minutes to secure his second-round berth in the Czech Republic.

Novak Djokovic may have missed out on completing a Grand Slam in 2021 but his "crazy" achievements across the year have received praise from Roger Federer. 

Djokovic fell at the final hurdle in his bid to secure a clean sweep of the majors, losing in straight sets to Daniil Medvedev at the US Open.

The Serbian's defeat at Flushing Meadows means Rod Laver remains the last man to claim all four majors in one year, the Australian doing so for a second time in 1969 having previously managed the feat seven years earlier. 

Neither Federer, who missed out on playing in New York due to knee surgery, nor Rafael Nadal have done so in their stellar careers, though the Swiss is certain a calendar slam is still possible.

"Will it actually happen again, that a player will win all four grand slams in their career? I think so," Federer said.

"We have seen with Rafael Nadal, Novak Djokovic and of course with me as well that this is possible.  

"It is extremely hard, of course. But I have the feeling, more than ever, that we can dominate on all kinds of ground where we have all found our own game.  

"The problem is mentally and physically it is not getting any easier for any of us. So, what Novak was able to accomplish this year has to be highly rated. It was absolute top class. It was crazy." 

Federer confirmed he would be out for "many months" when revealing he would require a third procedure on his problematic right knee in the space of 18 months.

However, the 40-year-old – who sits tied with long-time rivals Djokovic and Nadal on 20 grand slam singles titles – has suffered no setbacks in his recovery so far, putting him on course for a competitive return to the ATP Tour in the 2022 season.

"I'm feeling actually really good, considering, you know, that things are not as I hoped they would be, but I'm recovering well and the rehab is going really good, I must say," Federer said. 

"I've had no setbacks. You know, every day is a better day. I'm feeling strong and excited for what's to come."

Federer has not played since losing in straight sets to Hubert Hurkacz in the Wimbledon quarter-finals back in July.

Lorenzo Sonego made an impressive start at the Moselle Open as the fifth seed defeated Marton Fucsovics in straight sets. 

The Italian recorded his 25th win of the year on the ATP Tour on Monday, winning 6-3 6-2 in 73 minutes while not even conceding a break point to Fucsovics. 

"I was really focused," said Sonego. "Marton is a great player and it was a tough match. I liked my tennis and I am really happy.  

"I am confident because this year has been my best. I am now number 24 in the world, which is my best ranking. I have played my best tennis this year." 

Vasek Pospisil also moved through, beating home wildcard hope Gregoire Barrere 6-3 6-4. 

Hubert Hurkacz is the top seed at the ATP 250 event in Metz, with Gael Monfils and Andy Murray among the other stars yet to play their first match. 

At the Astana Open, which has the same ranking points available, Miomir Kecmanovic was a 6-4 6-2 winner over Fernando Verdasco. 

Seventh seed Laslo Djere, meanwhile, had to battle hard to end a four-match losing streak on the ATP Tour. He edged into the last 16 with a gruelling 6-4 3-6 6-4 win over Colombia's Daniel Elahi Galan. 

The highest-ranked players in the tournament are Russian Aslan Karatsev and home hope Alexander Bublik. 

Second seed Bublik will start his campaign against Kecmanovic, whose victory over Verdasco was his first win since the Tokyo Olympics in July.