Nick Kyrgios, John Isner and Reilly Opelka have been named by Team World captain John McEnroe as his final three picks for the Laver Cup.

The trio join Denis Shapovalov, Felix Auger-Aliassime and Diego Schwartzman for the team event which runs from September 24-26 at TD Garden in Boston.

Laver Cup newcomer Opelka rose to a career-high world number 23 ranking en route to his first ATP Masters 1000 final in Toronto and defeated world number three Stefanos Tsitsipas, who will play for Bjorn Borg's Team Europe.

Isner, who has featured for Team World since the inaugural event in 2017, reached the semi-finals in Toronto and claimed his 16th ATP Tour title in Atlanta at the start of August.

He described the Laver Cup as "a highlight of my year", adding: "To be on a team with guys we're normally competing against is so different and so much fun. We come together so well as a group, the chemistry is awesome and it's such a great environment to be part of."

Australian firebrand Kyrgios is a striking inclusion in Team World's roster, while Team Europe will be without their big three: Roger Federer, Rafael Nadal and Novak Djokovic.

Federer and Dominic Thiem were expected to take part in this year's event, though both were forced to withdraw with injuries.

However, Borg's men still boast six of the world's top 11. World number two Daniil Medvedev leads the line-up, with Tsitsipas and Tokyo Olympics gold medallist Alexander Zverev for company.

Casper Ruud, who collected a 14th win in his last 15 completed matches on tour when he beat Opelka on Wednesday, will feature, while Andrey Rublev and Wimbledon finalist Matteo Berrettini complete the six-man team.

Team Europe have landed the title in each of the three editions of the tournament so far, with Prague, Chicago and Geneva having served as hosts.

Cameron Norrie breezed past Nick Kyrgios and John Isner downed countryman Jack Sock to advance to the quarter-finals at the Atlanta Open on Thursday. 

The third-seeded Norrie defeated Kyrgios 6-1 6-4 in less than an hour as he tries for a second consecutive title after collecting his first ATP Tour championship at Los Cabos last week. 

The former University of Georgia star Isner, a five-time champion in Atlanta, beat Sock 7-6 (8-6) 6-4 despite serving only 13 aces after hitting 36 in his previous match. 

Second-seeded Jannik Sinner fell 7-6 (9-7) 6-4 to Australian qualifier Christopher O'Connell, leaving the tournament without its top two seeds after Milos Raonic was upset by Brandon Nakashima on Wednesday. 

O'Connell, ranked 132 in the world to Sinner's 23, had not won a main-draw match this year before defeating Denis Kudla in the opening round and will now face Isner in the quarters.

Norrie will meet Emil Ruusuvuori, who advanced when Benoit Paire retired down 3-0 in the third set after the pair had split the first two sets 4-6 6-4. 

Ruusuvuori is into his second career ATP quarter-final after making it to the semis at Nur-Sultan last year. 

Sixth seed John Isner sent down an Atlanta Open joint record 36 aces as he overcame countryman Jeffrey John Wolf in three sets on Tuesday.

World number 35 Isner was dominant on his first serve, winning 6-4 6-7 (3-7) 6-4 to claim a spot in the second round where he will face Jack Sock who beat Ricardas Berankis in three.

Isner's 36 aces equaled the previous Atlanta Open record set by Sam Querrey on Monday in his three-set win over Peter Gojowczyk.

American fifth seed Taylor Fritz also progressed on Tuesday with a 6-3 6-4 victory over Russian Evgeny Donskoy.

French seventh seed Benoit Paire got past Japan's Yasutaka Uchiyama 7-5 6-7 (2-7) 6-4, while enigmatic Australian Nick Kyrgios beat South African Kevin Anderson 7-6 (7-4) 6-3.

Teenage American talent Brandon Nakashima knocked out Trent Bryde, while Australian Chris O'Connell beat Denis Kudla and Finland's Emil Ruusuvuori got past Mackenzie McDonald 7-6 (7-3) 7-5.

Nakashima, who got a special exemption entry into the Atlanta Open, next takes on top seed Milos Raonic.

Wimbledon crowd favourite Nick Kyrgios retired hurt in his third-round match against Felix Auger-Aliassime on Saturday, hailing his opponent as a "hell of a player".

Kyrgios made headlines in the week with complaints over the condition of the grass courts at the All England Club, though the divisive Australian had looked sharp in wins over Ugo Humbert and Gianluca Mager.

He carried that form into his second career meeting with Canada's Auger-Aliassime, but as he charged to a 6-2 lead in the first set, Kyrgios sustained an apparent abdominal injury.

The 26-year-old received treatment on court, yet was clearly in distress as he attempted to continue, with Auger-Aliassime capitalising to take the second set 6-1 in just 22 minutes.

It signalled the end of the road for Kyrgios, who handed the win to the world number 19.

Despite his withdrawal, Kyrgios remained in good spirits.

Explaining his decision, Kyrgios said: "I haven't played this level of tennis in a long time, and obviously playing someone as good as Felix, my main weapon – my serve – to be firing on all cylinders and I just felt my abs, definitely did something in the first set.

"That's the way it goes. He's a hell of a player, he's going to do special things in this sport. Playing out here, having this support, has made me have a second wind. I reckon I'm going to come back and play for a bit longer.

"I did all I could to get here. I beat a heck of a player in the first round, played a great second round and just to get out here again, two sets, tried to play as long as I could, sorry I couldn't give you more today. But you'll see a lot of [Auger-Aliassime] in the future, and he's better looking too!"

For his part, Auger-Aliassime was equally as frustrated not to be able to see out what promised to be an entertaining match up.

"First of all, sorry for Nick, he was playing so good in the first set. It's really unfortunate in front of a packed crowd," he said.

"I think there were big expectations for this match, we were hoping to put on a good show, entertain the crowd, so it's unfortunate he had to retire. I hope it’s nothing too serious and he’ll be back on the US swing."

Dominic Thiem came from behind to edge Nick Kyrgios in a five-set epic in the Australian Open third round on Friday.

Thiem, last year's runner-up in Melbourne, fought back to win 4-6 4-6 6-3 6-4 6-4 on John Cain Arena.

The Austrian third seed was unable to match Kyrgios' energy levels early on, but the reigning US Open champion responded to reach the fourth round of a major for the 15th time in his career.

Thiem, who will face Grigor Dimitrov in the fourth round, was in impressive form after his slow start, finishing with 57 winners and just 28 unforced errors.

Kyrgios was getting the crowd – full of energy ahead of Victoria going into a five-day lockdown from Saturday due to coronavirus concerns – involved from the warm-up, while Thiem appeared flat.

An underarm ace saw Kyrgios take a two-sets-to-love lead as he looked in control before Thiem responded.

Coming from 15-40 down in the opening game of the third set, Thiem won 20 consecutive points on serve.

Kyrgios steadied and held after a marathon game to begin the fourth set, but he could not deny Thiem – who continued to hold serve comfortably – in the ninth as the Austrian broke with a cross-court forehand pass.

A point penalty for ball abuse appeared to bring Kyrgios to life, but Thiem saved a break point and served out the set.

The crucial and only break of the fifth set came for Thiem in the seventh game after several fine returns and he closed out his victory with a spectacular backhand winner down the line.

Nick Kyrgios has the weapons to overcome the "super physical" Dominic Thiem at the Australian Open on Friday.

The eccentric Australian continued to excite at Melbourne Park with a five-set win over Ugo Humbert in the second round, saving two match points.

Kyrgios, 25, is into the third round of a grand slam for the 15th time in his career, but it has been a difficult hurdle for him to cross. He is 6-8 in the third round of majors, although three of those wins – and just one loss – have come at the Australian Open.

While he has all the weapons, Kyrgios faces third seed Thiem, the US Open champion and last year's runner-up in Melbourne.

"He's probably one of the most physical guys on tour. He's an extremely good player. I have actually seen him progress. He's a bit older than I am. I actually saw him in juniors and then I saw him struggle for a couple years, futures, challies, and then to see him get to the top of the game. It's been actually pretty cool to see him develop and finally find what he needs to do to win matches," Kyrgios said about Thiem after overcoming Humbert.

"He trains like an absolute animal. He's consistent every day. And I actually have a lot of respect for him. I think his style of tennis is not easy to play. He's super physical, but I'm not even thinking about it. Like, I'm just hurting thinking about playing him right now."

He added: "Whatever happens against Thiem happens. I'm going to go out there, serve, play with instinct, and if it's enough, it's enough. If it isn't, I'm all right with that."

With much of the talk at the year's first major focused on the fast courts, Kyrgios' serve will be vital.

The Australian has seen 50 per cent of his first serves in the opening two rounds go unreturned, with 44 aces. He has also served at 72 per cent and won 81 per cent of the points when his first serve has gone in.

Thiem has recorded wins over Mikhail Kukushkin and Dominik Koepfer to begin the tournament, winning 13 of 27 return games. Kyrgios has won eight of 42 return games.

Kyrgios has been among the men more willing to serve and volley to begin the event, playing 26 such points and winning 16. He has also won 39 of 55 net points, while Thiem is an impressive 31 of 36.

Novak Djokovic is among those who have talked about the fast courts at Melbourne Park this year, and the world number one said that would suit the big servers. Thiem said he had never played on courts as fast at a grand slam so far in his career.

"I prefer last year's courts, if I could choose. It's pretty fast, as I said the days before. It's probably one of the fastest grand slam tournaments I've played so far," he said. "Well, we have to get used to it, yes. But if I have to choose, I would choose the last year's condition."

The opportunity is there for the big-hitting Kyrgios, but he will need to be at his best.

Novak Djokovic admitted there was plenty of room for improvement after coming through a "difficult spot" at the Australian Open, where Nick Kyrgios thrilled the crowd with an impressive comeback.

Top seed Djokovic was made to work for his 6-3 6-7 (7-3) 7-6 (7-2) 6-3 triumph against Frances Tiafoe as he reached the third round in Melbourne. 

Kyrgios is also through, albeit he even surprised himself by rallying from the brink of defeat to knock out 29th seed Ugo Humbert in the evening session. 

Stan Wawrinka was on the wrong of an upset on Wednesday, but there were no such problems for fellow seeds Dominic Thiem, Alexander Zverev, Diego Schwartzman and Milos Raonic. 

Meanwhile, Denis Shapovalov and Felix Auger-Aliassime will have to put their friendship to one side when they face each other next, the former setting up the all-Canadian clash by beating Bernard Tomic in three sets.

'PASSIVE' DJOKOVIC STILL MAKING PROGRESS

In the first meeting between the pair, the impressive Tiafoe went toe-to-toe with Djokovic on Rod Laver Arena.  

The 23-year-old American's performance – coupled with the Melbourne heat – made the eight-time Australian Open champion sweat, albeit Djokovic felt he could have made life easier for himself.

"I was at times not feeling my timing as well as I normally am. Credit to him. I think he has managed to come out with a great performance and quality of tennis. He put me in a difficult spot," he said. 

"I had my chances early in the second set. If I broke him there, maybe the course of the match would be different.   

"But again, he was holding his serve very well. I was not really using my break-point chances very well. At times I was too passive. Just wasn't feeling the ball today as well as I normally do." 

Next up for Djokovic is another player from the United States in the form of Taylor Fritz, who ousted compatriot Reilly Opelka in a five-set battle.

IN THE NICK OF TIME

Kyrgios described his clash with Humbert as "one of the craziest matches I've ever played" after prevailing 5-7 6-4 3-6 7-6 (7-2) 6-4 - much to the delight of an enthralled audience who watched the drama unfold on John Cain Arena.

The Australian smashed a racket, lost his cool with umpire Marijana Veljovic over a faulty net cord sensor and had to save a pair of match points before eventually coming out on top in a see-saw battle.

"I just remember, down that end, when I was a couple of match points down, I don't know what was going on," Kyrgios - who dropped to his knees after sealing victory - said in his on-court interview.

"If you were inside my head, there were some dark thoughts in there. But I live to fight another day and hopefully I can continue to play good tennis in front of you guys."

His reward is a clash with Thiem, the third seed having dismissed the challenge of German Dominik Koepfer in straight sets as he dropped just six games.

STAN-D AND DELIVER

Wawrinka appeared on course to survive a serious scare when he rallied from two sets down against Marton Fucsovics, but the Swiss was unable to seize on the chances that came his way in a tense tie-break. 

Fucsovics had needed over four hours to overcome wild card Marc Polmans in the previous round and, once again, found a way to get over the finishing line at the end of a Melbourne marathon. 

The Hungarian trailed 6-1 during the decisive breaker, yet hit back to stun the 17th seed 7-5 6-1 4-6 2-6 7-6 (11-9). For Wawrinka, there was frustration at the missed opportunities, albeit he also praised his conqueror. 
  
"From 6-1 up, I started to hesitate a little bit in the way I was playing," he said. "I wanted to put the ball maybe too much in and I [was] not going completely for my shots and that's when I started to miss a little bit and it helped him to come back in the match.  

"He was fighting well, he's a tough player, he's a good player and he deserved to win." 

World number one Novak Djokovic said he does not have "much respect" for outspoken Australian star Nick Kyrgios away from the tennis court.

Kyrgios has been critical of Djokovic in an ongoing feud with the 17-time grand slam champion, who was labelled a "tool" by the former following a list of requests made to Tennis Australia (TA) and the Victorian government for tennis players stuck in hotel quarantine amid the coronavirus pandemic.

Former world number 13 Kyrgios was also critical of Djokovic's decision to stage the Adria Tour in Europe last August – in the midst of the COVID-19 crisis – having previously dubbed the Serb star "cringeworthy".

Djokovic rekindled his rivalry with Kyrgios after being asked about the 25-year-old on the eve of the Australian Open.

"I've said this before," Djokovic told reporters on Sunday. "I think he's good for the sport. Obviously he's someone that is different. He goes about his tennis, he goes about his off court things in his own authentic way. 

"I have respect for him. I have respect for everyone else really because everyone has a right and freedom to choose how they want to express themselves, what they want to do. My respect goes to him for the tennis he's playing. I think he's very talented guy. He's got a big game. He has proven that he has a quality to beat any player really in the world in the past.

"Off the court, I don't have much respect for him, to be honest. That's where I'll close it. I really don't have any further comments for him, his own comments for me or anything else he's trying to do."

Djokovic has won the past two Australian Open finals as he eyes a record-extending ninth Melbourne Park crown.

The 33-year-old, who opens his title defence against Jeremy Chardy on Monday, has won the Australian Open every time he has reached the semi-finals.

Djokovic has reached at least the semi-finals in seven of his last nine grand slam tournaments, winning five of them.

No male has won more Australian Open men's singles titles than Djokovic, who said: "It's a love affair. Probably something similar maybe not like Rafa [Nadal] has with the French Open, but I've been feeling more comfortable on the court each year that I've been coming back. 

"The more you win, obviously the more confidence you have and the more pleasant you feel on the court. It just feels right. If you're in the right state of mind, regardless of the surface, you have a better chance to play at your best.

"When I stepped on the court this year for the first time in the practice session, I relived some of the memories from last year, also the other years that I won the tournament here.

"It just gives me great sensation, great feeling, confidence. It feels right. It feels like the place where I should be and where I have historically always been able to perform my best tennis. Hopefully can be another successful year."

Asked if he still feels nerves, Djokovic – who is looking to close the gap on Rafael Nadal and Roger Federer (both 20) for the most slam trophies – added: "Every match, every match. Every single match. I don't want to speak on behalf of the other athletes, but I just feel like it's almost impossible to eliminate that kind of pressure, anticipation, the nerves coming into any match really for an athlete. At least in my case.

"It's just that I managed over the years to train myself, I think with the experience and with also the dedication that I had off the court to the mental preparation, that helped me react better to those kind of emotions. Sometimes I don't manage to overcome the pressures and the stress and nerves. Sometimes I do. It really just depends. Even though I've been blessed to experience a lot of success, especially here in Australia, but also in my career. I still feel that those failures, if you want to call them that way, even though I don't believe in failures, I just believe in opportunities to improve, kind of the lessons to be learned, but in those matches you lose, big matches, that's where you learn the most.

"That's where you're facing the kind of wall mentally. You're upset. You have a lot of different things happening, and you feel like you let yourself down. That's where it's the biggest opportunity for you to really address that and become stronger, more capable. You can get to know yourself a little bit on deeper levels. It still happens to me.

"Every single tournament, regardless of my previous success, of course I do feel that I have more confidence, more experience, maybe more training in understanding how to deal with these specific situations when I'm coming on the big court, being expected to win 99 per cent of the matches that I play.

"But it's still there. It's still there. I don't think it's ever going to go away. Especially when the occasion is big, when you're playing for the biggest trophies."

Novak Djokovic continued his perfect record at the ATP Cup to help Serbia beat Canada in their opening tie.

The world number one won all eight of his rubbers in the 2020 tournament and made a fine start to this event by battling to a 7-5 7-5 win over Denis Shapovalov in Melbourne.

Milos Raonic had earlier put Canada in front when he beat Dusan Lajovic 6-3 6-4, meaning Djokovic had to return for a decisive doubles clash alongside Filip Krajinovic. 

The Serbians prevailed, winning 7-5 7-6 (7-4) against Shapovalov and Raonic.

"Filip Krajinovic was the key," Djokovic said after the doubles triumph extended his undefeated run to 10. 

"The way he played is phenomenal. He came out with very solid returning. He found his serve, great rhythm. He just played some really key shots in the second set when we needed it the most."

Of his singles win, Djokovic added: "It was a very close match. Playing Shapo is always a great challenge on hard courts. 

"He's such a dynamic, explosive player; very talented. I thought we played on a very high level, so I'm really pleased with how I've started the season.

"This is the best way to kickstart the season, playing for your country.

"We don't get to see crowds in the tennis stadiums these days so much, so it's definitely a blessing. I'm really grateful to see you guys here in the stands."

SPAIN WIN WITHOUT NADAL

Defending champions Spain were without Rafael Nadal for their tie against Australia, but they still prevailed.

Pablo Carreno Busta had few problems seeing off John Millman 6-2 6-4.

And Roberto Bautista Agut ensured the tie was won before the doubles by emerging triumphant in an entertaining encounter with Alex de Minaur, which the Spaniard won 4-6 6-4 6-4.

Nadal, who is battling a back problem, hopes to return on Thursday when Spain take on Greece.

Elsewhere, Austria fell to a 2-1 loss against Italy, as US Open champion Dominic Thiem struggled.

After team-mate Dennis Novak had superbly beaten Fabio Fognini, world number three Thiem fell to a surprise 6-2 6-4 loss against Matteo Berrettini, with Austria going on to lose the decisive doubles.

Andrey Rublev and Daniil Medvedev beat Guido Pella and Diego Schwartzman respectively as Russia produced an impressive performance to beat Argentina.

Elsewhere, at the Murray River Open, Nick Kyrgios made a winning start to his comeback after a year out of action.

He did not have it easy against the unheralded Frenchman Alexandre Muller, but salvaged a 3-6 6-4 7-6 (7-4) victory to book a second-round meeting with fellow Australian Harry Bourchier.

Nick Kyrgios has labelled Novak Djokovic "a tool" after the world number one reportedly issued a list of demands for players under strict quarantine conditions ahead of the Australian Open.

Defending women's singles champion Sofia Kenin is among 72 players who are consigned to their hotel rooms due to positive coronavirus tests on flights they took to head out for the first grand slam of the year.

Players have posted social media clips of them training and in their rooms, with some complaining about the conditions they are having to contend with for 14 days.

Bernard Tomic's girlfriend, Vanessa Sierra, expressed her grievances over the standard of food and having to wash her own hair and dishes during her period of quarantine with the world number 228 so far.

Djokovic does not have to adhere to such strict rules in Adelaide, where he is due to play in an exhibition tournament before the Melbourne major, as he arrived on a virus-free flight.

Yet the 17-time grand slam champion is said to have asked for less time in isolation for players, requested they are given private housing with access to training courts, and better food.

Kyrgios tweeted on Monday: "Djokovic is a tool. I don't mind Bernie [Tomic] but his Mrs obviously has no perspective, ridiculous scenes Man."

Three weeks before the Australian Open is due to get underway, Victorian premier Daniel Andrews said the players will not be getting any "special treatment."

He said: "The virus doesn't treat you specially, so neither do we.

"I know there's been a bit of chatter from a number of players about the rules.

"The rules apply to them as they apply to everybody else and they were all briefed on that before they came and that was the condition on which they came. So, there's no special treatment here."