Top seed Denis Shapovalov's Swiss Open Gstaad campaign came to an abrupt end as Vit Kopriva provided a second-round shock to eliminate the Wimbledon semi-finalist.

The world number 10, who has recently been praised by both Roger Federer and Rafael Nadal, took the first set 6-2 with ease before Kopriva, making his ATP Tour debut this week, emphatically fought back 6-3 6-2 to secure a memorable comeback victory.

Number three seed Casper Ruud battled past Dennis Novak 6-4 7-6 (7-5), while Benoit Paire, who only had two ATP wins in 2021 before the Hamburg European Open last week, was 6-4 to the good before Tallon Griekspoor was forced to retire due to injury.

Ruud, who has already won two ATP events in 2021 and three in his career, will now meet sixth seed Paire in the quarter-final stage.

But eighth seed Feliciano Lopez did not enjoy similar success as the world number 96 Mikael Ymer fought past the Spaniard to win 6-7 (6-8) 7-6 (9-7) 6-4 and set-up a quarter-final clash with Kopriva.

At the Umag Open in Croatia, third seed Filip Krajinovic breezed past Radu Albot to record a 6-4 6-2 win.

Krajinovic's countryman and number two ranked player Dusan Lajovic also went through with a 7-5 6-4 win against Bernabe Zapata Miralles.

Novak Djokovic has been burned by high expectations at the Olympics before, so it was little surprise that he should express only guarded optimism on the eve of the Tokyo Games.

The Serbian, who has won the Australian Open, French Open and Wimbledon already in 2021, is chasing the gold medal that would leave him one step away from the first tennis calendar 'Golden Slam' by a man.

Should he triumph in Japan over the next fortnight, Djokovic will head to the US Open in late August needing to win in New York to complete the full set.

Steffi Graf, who in 1988 won all the slams and gold at the Seoul Olympics, is the only player in tennis history to have completed such a sensational season.

Djokovic said such a feat was becoming a "more and more realistic" target, as he spoke in a Serbia team news conference, but the last time he stepped off the singles court at an Olympic Games, he was in tears, having lost in the first round at Rio to Juan Martin del Potro.

There is no danger of Djokovic running into his Olympic nemesis in Tokyo, with Del Potro, who also beat Djokovic in a bronze-medal match at the London 2012 Olympics, not a part of Argentina's squad as he battles back from four knee operations.

Looking at his own prospects for Tokyo and the rest of the year, Djokovic said: "It is still a long way to go ... I put myself in a very good position. But I will take things very slowly and cautiously.

"It's an approach I need to have because in the past I wasn't probably fully experienced in that approach. And I started to feel there were a lot of distractions around that influenced my performance.

"I know there are a lot of things on the line, a lot of history on the line. I'm privileged to be in this position. I worked very hard to be here, with my team, of course. But let's talk about history if everything goes great."

After his singles loss in Rio, Djokovic and Nenad Zimonjic lost in the second round of doubles to Brazilians Bruno Soares and Marcelo Melo.

A bronze from Beijing 2008 is all Djokovic has to show for his Olympics career to date, but he is a hot favourite for the title in Tokyo, where he will start against Bolivia's world number 139 Hugo Dellien.

The 34-year-old Djokovic said he "would be delighted to ask" Graf how she achieved her 1988 clean sweep.

"When I was thinking about her ultimate achievement ... I did not think it... I don't want to say 'achievable', but [I thought] there was a slim chance that someone could make it again, both male and female," Djokovic said.

"But right now it seems more and more realistic. Of course, it is one of my goals and dreams."

Djokovic has neither Roger Federer nor Rafael Nadal as rivals in Tokyo, with Federer missing after reporting a knee injury setback and Nadal electing to give the event a miss.

The 'Big Three' each have 20 grand slam titles now, following Djokovic's hot streak, and the Serbian admits it is unusual for both superstars to be absent.

"I have not experienced too many big tournaments in the past 15 years without Roger and Rafa playing. So it's a little bit strange," Djokovic said. "I'm used to seeing at least one of them. But still, some of the best players in the world are here.

"The guys who are in the top six, seven in the world, they are the biggest competitors or candidates for winning a medal. But potentially I am meeting with them in the later rounds."

After winning Wimbledon for a sixth time, Djokovic surprised many by claiming he could skip the Olympics, but he was reeled in by the appeal of representing his country, perhaps for the final time in the Games.

"Without the key element of any sports events – the crowds, the fans, that energy – it's different, but it is still the Olympic Games," he said.

"I was in a dilemma for a little bit, but I decided to come, and I'm glad because there are many more things that are beautiful about the Olympic Games. So I will try to focus on those things."

Novak Djokovic has leapt from one bubble into another as he attempts to become the first man in tennis history to win all four grand slams and Olympic gold in the same year.

The only men to have won each of the singles majors across their careers, plus Olympic gold, are Andre Agassi and Rafael Nadal, and now Djokovic aims to move to the brink of winning all five in his remarkable 2021 season.

Fresh from dominating at Wimbledon, and with the Australian and French Open titles already in the bag, Djokovic heads into the Tokyo Games as a red-hot favourite, seeking to set himself up to complete a historic campaign at the US Open.

Naomi Osaka will enter the Games with almost as much expectation behind her too, the reigning US Open and Australian Open champion eyeing glory for hosts Japan.

But tennis has thrown up a host of shock results in its short Olympic history. Here, Stats Perform looks at the sport's place in the Games.

WHO'S IN, WHO'S OUT, AND WHAT DOES ALL THIS MEAN?

Serena Williams, Roger Federer and Rafael Nadal have all opted out of the Olympics.

Williams made her mind up prior to suffering a leg injury at Wimbledon, although she is already a member of the career Golden Slam club.

Federer reached his decision after revealing he also suffered a physical setback at the All England Club, and Nadal elected to take a two-month break after relinquishing his French Open title.

Don't expect to see them again at the Olympics, given Williams and Federer will be pushing 43 by Paris 2024, and Nadal will be 38. Federer won a doubles gold with Stan Wawrinka in 2008, but his singles peak was the silver medal he earned in 2012, Andy Murray crushing Swiss hopes in the final at Wimbledon.

Dominic Thiem, Bianca Andreescu, Nick Kyrgios, Simona Halep, Angelique Kerber, Victoria Azarenka and Denis Shapovalov are among other confirmed absentees, with fitness issues a factor for some, less so for others.

The COVID-19 crisis is a mitigating factor in why so many stars are staying away, and directly responsible in the case of some players, such as Britain's Johanna Konta and Dan Evans, who both tested positive recently.

But tennis was only fully restored to the Olympic programme in 1988, after being dropped post 1924, and if players are seen to be favouring the grand slams over the Games, that is not such a great look for the sport.

At a time when the International Olympic Committee has shown it is willing to shake up the sports on its programme, tennis could perhaps do with a headline-making Tokyo 2020.

Murray, the two-time defending men's champion, will target an improbable hat-trick. A hat-trick for the injury-hit former world number one would be a sensation, and Osaka landing gold in the women's tournament would surely be one of the great moments of the Games.

DJOKOVIC FOLLOWING IN THE FOOTSTEPS OF GRAF

When Steffi Graf beat Gabriela Sabatini in the women's singles final at Seoul, it completed what we know now as the calendar 'Golden Slam'. She had already won the Australian Open, French Open, Wimbledon and the US Open, and the feat of the then 19-year-old West German has yet to be repeated.

Now Djokovic is three-fifths of the way to a similar clean sweep of the majors and the Olympics, with the US Open getting under way on August 30 in New York.

He teetered on not going to Tokyo, and perhaps he is to some extent endangering his chances at Flushing Meadows by spending more time travelling and enduring bubble life, while others rest up.

But Djokovic is a fiercely proud Serbian and could not resist a great chance of winning gold for his country. He landed bronze at the 2008 Games in Beijing but in 2012 he lost to Juan Martin del Potro in the bronze-medal match, and a cruel draw at Rio four years later saw him assigned Del Potro in the first round.

Top seed Djokovic bowed out in two tie-breaks to the powerful Argentinian, describing the outcome as "one of the toughest losses in my career".

There is no danger of a hat-trick of defeats to Del Potro, which may help Djokovic. Del Potro has been battling for two years to get back to fitness, undergoing four rounds of right knee surgery in a bid to get back on tour.

RAISING THE BAR AT THE OLYMPICS

How the Olympic village functions in Tokyo will be distinctly different to at previous Games, given the pandemic restrictions in place that could be a real buzzkill.

But in the past there have been countless cases of athletes becoming inspired by their surroundings and going on to perform above their usual level.

It can be a party village, and it can also be an eyebrow-raising experience as global superstars rub shoulders with competitors who might struggle for recognition in their home towns. More than anything, the shared team experience, fighting for a collective cause, can make a middling athlete believe they can be great.

Monica Puig was a massive tennis outsider in 2016 but the then world number 34 won the women's singles, stunning Angelique Kerber in the final after beating Petra Kvitova and Garbine Muguruza en route. That gave Puerto Rico their first ever Olympic gold medal.

In 1992, a tournament that featured the likes of Pete Sampras, Jim Courier, Stefan Edberg and Boris Becker finished with a staggering final match-up of Marc Rosset versus Jordi Arrese, who in his home city of Barcelona was edged out 8-6 in the fifth set by the Swiss world number 43. Nobody would have predicted that head to head for gold.

Similarly, at Athens 2004, Nicolas Massu beat Mardy Fish in the gold medal match of a tournament that featured Federer, Andy Roddick, Carlos Moya and Tim Henman.

In the 1996 Atlanta Games, Lindsay Davenport, who had just turned 20, took inspiration from being the daughter of an Olympian, with dad Wink having played volleyball for the United States at Mexico City in 1968.

Davenport was beginning to make an impact on the WTA Tour but was only the ninth seed at the Olympics, yet she swept through the rounds before sinking Arantxa Sanchez Vicario 7-6 (10-8) 6-2 in the final.

"It's like one of those things I look back on and I'm like, 'Was that me?'," Davenport told The Tennis Podcast last year.

"It doesn't seem like it was real. I'd made the transition to the pro tour pretty well, but I liked hanging out between eight and 16 in the rankings. I was very insecure, unsure of what could I do. I liked doing well but I wasn't sure I wanted to do too well because it seemed really overwhelming to be one of those top players.

"Here I go at 20 years old to Atlanta for two or three weeks, in a setting that seemed so comfortable. Look at all these athletes, you have all different shapes and sizes, you have players that are really working hard but have so much in common and you get to hang out with them, breakfast, lunch, dinner in the village."

Davenport was a future world number one and three-time grand slam singles champion, but at this point in her career being an American at an Olympics in the United States was just a thrill.

"You're sharing this with your team-mates who are some of my best friends in Mary Joe Fernandez, Monica Seles. It was the best time ever," she said.

"By the time the tournament actually started we were like, 'Yeah, I'll go play my match and then we'll go back to the village and we'll hang out', and everything went so fast in those few weeks.

"And there I was left standing, winning at the end because I was so incredibly happy and excited with everything that was going on. I kind of forgot what was my job.

"When it became a reality of even just making the team in '96, it was so huge also for my family with having a second generation Olympian."

Roger Federer is in the draw for the US Open, but it remains unclear whether he will be fit to take part in the final grand slam of the year.

The United States Tennis Association confirmed on Wednesday that Federer was one of six former men's champions to receive direct entry into the draw.

Federer this month withdrew from the Olympic Games, citing a setback with his knee, on which he had two surgeries in 2020.

The Swiss, though, expressed his desire to return the tour, with Flushing Meadows providing his last chance to add to his tally of 20 major titles in 2021.

A five-time winner in New York, Federer has not reached the final at the US Open since 2015.

In the women's singles draw, Naomi Osaka and Serena Williams have each received direct entries into the draw.

Reigning champion Osaka missed Wimbledon having withdrawn from the French Open after the first round to protect her well-being amid a fallout following her decision to not attend post-match media conferences.

Williams is still awaiting a record-tying 24th grand slam title, the 39-year-old forced to retire from her first-round match at Wimbledon because of an injury to her right leg.

Roberto Bautista Agut crashed out to Arthur Rinderknech in the second round of the Swiss Open Gstaad on Wednesday, while fifth seed Federico Delbonis also failed to progress.

Rinderknech, who is ranked exactly 100th in the world, picked up the biggest win of his career in style as he dispatched of second seed Agut with a comfortable 6-2 6-4 victory

In another upset, world number 155 Hugo Gaston laid down an early marker with a first-set demolition of Delbonis, who lost out to eventual winner Pablo Carreno Busta in the Hamburg European Open semi-finals last week, before he triumphed in three sets, 6-0 6-7 (2-7) 7-6 (7-3).

Fourth seed Cristian Garin cruised past Marc Polmans 6-3 6-0 to wrap the match up in less than an hour and seal his fifth ATP quarter-final of 2021.

Another semi-finalist in Hamburg, Laslo Djere survived a second-set scare to eliminate Zizou Bergs with a 6-2 4-6 6-2 win, which sets up a last-eight tie with Rinderknech.

At the Croatia Open in Umag, fourth seed Richard Gasquet battled past qualifier Alessandro Giannessi to secure a 7-6 (7-4) 6-4 victory.

Top seed Albert Ramos-Vinolas also progressed, winning 7-5 6-4 to eliminate Duje Ajdukovic on his home turf.

Fresh off the back of semi-final appearances at the Hamburg European Open, Federico Delbonis and Laslo Djere coasted through their respective first-round matches on the second day of the Swiss Open Gstaad, which included no upsets at the round-of-32 stage.

Delbonis, who is seeded fifth and lost to eventual winner Pablo Carenno Busta last week in Hamburg, cruised to a 6-3 6-3 victory against Leandro Riedi as the Swiss player struggled to make home advantage count.

Seventh seed and loser of the other semi-final in Germany last week, Djere continued his good form and wasted no time in thrashing Brazilian Thiago Seyboth Wild 6-4 6-3.

The other game on day two saw Dennis Novak dispatch of Kacper Zuk 6-4 6-4 and that straight-sets victory means the Austrian will next face the number three seeded player Casper Ruud, who won the Nordea Open last week to secure his third ATP title and second of 2021.

Alongside Ruud, the three other top four seeds - Denis Shapovalov, Roberto Bautista Agut and Cristian Garin - will now enter the draw, after benefiting from byes in the first round of the competition.

There was a surprise at the Croatia Open in Umag, though. Fifth seed Aljaz Bedene went down 6-1- 6-4 to Marco Cecchinato, who will now challenge fellow qualifier Damir Dzumhur to set up a potential quarter-final clash with Richard Gasquet if the Frenchman makes it through his round-of-16 tie.

Benoit Paire made a strong start as the Swiss Open Gstaad got under way on Monday.

Number six seed Paire was a 6-3 7-6 (7-2) winner in his first-round match against Jozef Kovalik.

The Frenchman was not broken in the match, saving all eight of the break-point opportunities he offered up to Kovalik during a competitive 85-minute contest.

Paire's win follows a quarter-final appearance at the Hamburg European Open last week as the 32-year-old begins to recover from a dreadful first half of 2021.

Prior to his run in Hamburg, Paire had only won two ATP Tour matches this year.

Mikael Ymer had to come from behind before he progressed with a 4-6 6-3 6-3 win over lucky loser Enzo Couacaud.

The top four seeds at the ATP 250 event – led by Wimbledon semi-finalist Denis Shapovalov – get a bye through the first round and are therefore yet to begin their campaigns.

At the Croatia Open Umag, meanwhile, Radu Albot came out on top as he claimed a three-set victory over Holger Rune, with top seed Albert Ramos-Vinolas and defending champion Dusan Lajovic not in action on day one.

Kevin Anderson landed his first title since January 2019 as the former Wimbledon finalist triumphed at the Hall of Fame Open on Sunday.

The one-time world number five served 16 aces in a 7-6 (10-8) 6-4 win over 20-year-old American Jenson Brooksby at the tournament in Newport, Rhode Island.

Playing the third grass-court final of his professional career, after being runner-up at Queen's Club in 2015 and at Wimbledon in 2018, Anderson outfought Brooksby to land a seventh ATP title.

Now ranked at a relatively lowly 113th, the 35-year-old South African former world number five saw off top seed Alexander Bublik in the semi-finals before getting the better of Californian prospect Brooksby in the title match.

"It's been a pretty tough run with some injuries," Anderson said, quoted on the ATP website. "But to be back here at the International Tennis Hall of Fame with such history, this couldn't be a better week for me to start, hopefully, my comeback.

"I'm very motivated to get back. But it all starts with each match, and I was able to really grind it out."

Anderson's last title had come on hard courts at the Maharashtra Open in Pune, India, where he got the better of Ivo Karlovic in a match where all three sets went to tie-breaks, and where Karlovic fired 36 aces in a losing cause.

Italy's Matteo Berrettini has become the latest high-profile tennis player to pull out of the Tokyo Olympics after injuring his thigh.

The world number eight, who had a bandaged leg in last week's Wimbledon final loss to Novak Djokovic, joins Rafael Nadal, Roger Federer and Stan Wawrinka in withdrawing from the men's event.

Serena Williams, Simona Halep, Victoria Azarenka, Johanna Konta, Bianca Andreescu and Angelique Kerber are among those to have already announced their decision to skip the women's tournament in Tokyo.

Berrettini, the first Italian to reach a Wimbledon singles final, announced his decision in an Instagram post on Sunday.

The 25-year-old's announcement comes a day after compatriot Francesco Molinari revealed he will not be taking part in the golf event at the Olympics.

"I am extremely disappointed to announce my withdrawal from the Tokyo Olympic Games," Berrettini said.

"I had an MRI scan yesterday on the thigh injury I sustained during Wimbledon and was informed I will not be able to compete for a couple of weeks."

The Olympic tennis events begin on July 24 and run through to August 1.

However, the deadline to name new athletes passed on Friday, so the Italian National Olympic Committee will not be able to name a replacement to join Fabio Fognini, Lorenzo Sonego and Lorenzo Musetti.

"Representing Italy is the biggest honour for me so it is devastating to miss the Olympics," Berrettini added.

"I wish the entire Italian team the best of luck in Tokyo. I will be supporting you all the way."

Despite the flurry of withdrawals, world number one Djokovic confirmed this week that he will enter the Olympic Games.

Djokovic travels to Japan in pursuit of a ground-breaking achievement, the Serbian just two titles – the Olympics and US Open – away from a first men's Golden Slam after triumphing at the Australian Open, French Open and Wimbledon in 2021

Casper Ruud won his third ATP Tour title on Sunday thanks to a straightforward win over Federico Coria in the Nordea Open final.

The Norwegian needed just under 90 minutes to see off Coria, who was competing in his maiden tour-level final, getting the job done to win 6-3 6-3.

Ruud's electric start set the tone for the contest, as he raced into a 4-0 lead thanks to successive breaks – although Coria broke back to make it 4-1, his opponent's wobble was only brief.

Coria ensured the match was a little tighter initially in the second set, but Ruud's class showed as he rattled off three breaks on the trot and eventually converted his fifth match point in front of a joyous support.

"It was an incredible week, maybe the best week of my life," Ruud said after sealing the title without losing a single set.

"It's an incredible feeling playing here in Bastad with the Swedish, Norwegian and Danish support. There is nothing like that home crowd feeling.

"To win here means a lot. You get a little extra nervous as the No. 1 seed. Me and my father [former player Christian Ruud] have been joking about when I am going to beat him at this and this, and now I think I have beaten him in everything!

"The Ruud family can finally bring the trophy home to Norway. It is a special feeling having him here with me."

Pablo Carreno Busta beat Filip Krajinovic in the final of the Hamburg European Open to lift his first ATP 500 trophy.

Spanish second seed Carreno Busta wrapped up a convincing 6-2 6-4 win over Krajinovic of Serbia in one hour and 23 minutes.

Krajinovic, who beat Stefanos Tsitsipas in the quarter-finals, had no answer to Carreno Busta's serve as he won 81 per cent (21/26) of his first-service points.

Carreno Busta broke Krajinovic's serve twice in the first set before he served out. 

Krajinovic showed more fight in the second set, but he was unable to create a break chance, and when he offered one to Carreno Busta his opponent seized it.

The victory gave world number 13 Carreno Busta, who did not drop a set in the tournament, his 17th win on clay this season.

Filip Krajinovic will take on Pablo Carreno Busta in the Hamburg European Open final on Sunday.

A memorable week for Krajinovic continued as he saw off fellow Serbian Laslo Djere 6-4 6-2 in his semi-final.

Sixth seed Krajinovic defeated Stefanos Tsitsipas in the quarter-finals and ensured he followed up on that surprise victory with a dominant display against Djere on Saturday.

The victor committed only seven unforced errors in the match, while conceding just two break points in the contest.

Second seed Carreno Busta has not dropped a set all week and kept that run going with a 7-6 (7-2) 6-3 win over Federico Delbonis.

Carreno Busta needed just under two hours to see off a battling Delbonis, with neither player offering up a single break point in a first set that went the distance.

The Spaniard won five straight points to take the tie-break and continued that momentum into the second set when he broke Delbonis twice.

Neither Carreno Busta nor Krajinovic has ever won a tournament at ATP 500 level or above.

Carreno Busta has five career titles, but all of those are at ATP 250 level, losing to Dominic Thiem in his only showpiece appearance at this level at the Rio Open back in 2017.

Krajinovic, meanwhile, has lost all three of the career finals he has reached.

"I enjoy playing here, I feel comfortable here," Carreno Busta said. "It is my most important match this year on Sunday - I need to be really focused until the end.

"[Delbonis] is a really tough player and my level was very good. I probably played better in the second set, but I continued fighting all the time."

At the Nordea Open in Bastad, Sweden, top seed Casper Ruud was comfortable as he defeated Roberto Carballes Baena 6-1 6-4 to earn a place in the final.

Ruud needed just 79 minutes to do the job, breaking Carballes Baena on five occasions. 

He has only played two matches – both comfortable wins – to reach the final after a walkover against Henri Laaksonen in the quarters.

Rising star Ruud will bid for his second ATP title of the year and the third of his career against Federico Coria on Sunday.

Coria also had a comfortable last-four tie, seeing off Germany's Yannick Hanfmann 6-2 6 -1, with the win meaning the 29-year-old reached his maiden career tour final.

"I am very happy - it is my first final," said world number 77 Coria, who beat second seed Cristian Garin in the last eight.

"I played the best tennis of my life in this match. It is amazing here in Bastad, it is beautiful."

Stefanos Tsitsipas will head into the Tokyo Olympics on the back of a disappointing quarter-final exit at the Hamburg European Open.

The world number four made a fast start to his match against Filip Krajinovic, winning the opening five games, but fell away to lose in three sets after an hour and 59 minutes.

Tsitsipas is due to represent Greece at the behind-closed-doors Games in Japan, where he will be among the medal favourites.

His racket bizarrely fell apart in the second set against Krajinovic, with Tsitsipas left clutching just the handle as the head broke off when he attempted a backhand.

Despite reaching for a replacement racket, Tsitsipas could not get the better of his 44th-ranked Serbian opponent.

Krajinovic said, according to the ATP website: "He started really well, really aggressively. I could not find my game, could not find my serve, he was overpowering me. But at the end of the first set, I started to feel better, I was going for my shots.

"It paid off in the end. I am happy to beat Tsitsipas, he is an amazing player. I always play well here, and I hope I keep playing well here."

Krajinovic advances to take on a fellow Serbian, Laslo Djere, in the semi-finals, after Djere swept to a 6-2 6-2 win over Georgian Nikoloz Basilashvili.

Spanish second seed Pablo Carreno Busta prevented a third Serbian reaching the final four, beating Dusan Lajovic 7-6 (7-4) 6-3, and he will face Federico Delbonis on Saturday.

At the Nordea Open in Bastad, Sweden, top seed Casper Ruud had his path to the semi-finals smoothed by the withdrawal of scheduled opponent Henri Laaksonen due to injury.

That walkover means Norwegian Ruud will next tackle Roberto Carballes Baena, who beat Slovakian Norbert Gombos 6-4 6-2.

Chilean second seed Cristian Garin bowed out, beaten 6-4 4-6 6-2 by Argentinian Federico Coria. Coria's semi-final opponent will be Germany's Yannick Hanfmann, a 6-4 6-3 victor over French qualifier Arthur Rinderknech.

Novak Djokovic has confirmed he will enter the Olympic Games in Tokyo, with the world number one just two titles away from a first men's Golden Slam.

Rivals Rafael Nadal and Roger Federer, citing respective scheduling and injury issues, have each withdrawn from Tokyo 2020.

But Djokovic confirmed on Thursday he will travel to Japan in pursuit of a groundbreaking achievement.

Only women's tour legend Steffi Graf has previously won all four majors and the Olympics in the same year, doing so in 1988.

Doubles superstars Bob and Mike Bryan held all five titles at once but collected them across 2012 and 2013, while Andre Agassi and Nadal are the only two men's singles players to achieve the feat across an entire career.

Djokovic has already triumphed at the Australian Open, French Open and Wimbledon in 2021, leaving Tokyo and the US Open still to conquer.

The 20-time grand slam champion – a record he tied at the All England Club on Sunday – has entered the Games three times previously but earned only a single bronze medal. Andy Murray is the two-time defending champion.

At Flushing Meadows, Djokovic is a three-time winner.

The 34-year-old confirmed his Olympics plans in a social media post as he sent a message to a young Japanese fan celebrating his sixth birthday.

"Cannot disappoint my little friend Koujirou," Djokovic wrote. "I booked my flight for Tokyo and will proudly be joining #TeamSerbia for the Olympics."

He had said following his Wimbledon win last week: "My plan was always to go to Olympic Games, but right now I'm a little bit divided."

Djokovic added limitations on his travelling party and potentially being unable to watch fellow athletes had reduced the likelihood of an appearance to "50-50".

But he will now feature, even if former Wimbledon champion Pat Cash believes the calendar Grand Slam – winning the four majors but not the Olympics – has to be the Serbian's priority.

Cash told Stats Perform: "It's the Olympics, okay – maybe he wants to do that, but certainly his goal is now to try and win all four grand slams in the calendar year.

"He has done four in a row, but he hasn't done them in the same year, which is very, very tough to do.

"There is a reason why I think one person has done it in [men's] professional tennis – Rod Laver and it was in 1969, so it's not easy to do.

"But I really do think it's in his sights and that has got to be his priority.

"It's absolutely the absolute peak of our sport to win all four grand slams in one year."

Casper Ruud fed off the growing expectation that surrounds him as he took a convincing first step in the Nordea Open.

The 22-year-old Norwegian has rocketed from outside the top 50 to 16th currently in the world rankings in just 18 months, and he is the top seed this week in Sweden.

Such a status is all rather novel for Ruud, but he breezed to a 6-0 6-2 win over 18-year-old Danish wildcard Holger Vitus Nodskov Rune on Thursday.

That carried him through to a quarter-final meeting with Swiss player Henri Laaksonen.

Ruud is back on clay this week, having enjoyed great success on the surface already this season, reaching semi-finals of the Masters 1000 events in Madrid and Monte Carlo, while also winning a title in Geneva.

A first-round exit on the Wimbledon grass followed those positive results, so another event on clay comes as a boost.

"It is a surface I have had the most success of my career, it is great to be back here in Bastad," Ruud said after crushing Rune's hopes.

"There is a bit of extra pressure [being the top seed]. In a match like this against a fellow Scandinavian younger player, it is even more."

He added, quoted by the ATP website: "I think I was very professional in my mindset today. I played a match without any errors really from the first to the last point.

"It is a nice feeling being the top seed but also pressure. I felt great crowd support, it is nice to feel that energy."

Qualifier Laaksonen beat Elias Ymer 6-2 7-5, while third seed Fabio Fognini was bounced out of the tournament, losing 6-3 1-6 6-4 to Spain's world number 97 Roberto Carballes Baena, who will tackle Slovakian Gombos in the last-eight stage on Friday.

At the Hamburg European Open, Pablo Carreno Busta justified his standing as second seed with a 7-5 6-3 win over fellow Spaniard Carlos Taberner to reach the quarter-finals.

Stefanos Tsitsipas is the top seed this week at the tournament in Germany and won through to the last eight on Wednesday.

Others to move through the rounds in Hamburg on Thursday included Dusan Lajovic and Federico Delbonis, the latter advancing with a handy 6-3 7-6 (7-4) win over fourth seed Albert Ramos-Vinolas.