Fifth seed Filip Krajinovic made a comfortable start to his Sofia Open campaign on Wednesday, defeating Alexandar Lazarov 6-0 6-3.

Krajinovic was the only seeded player in action and he was dominant against home hope Lazarov, who is ranked 462 in the world.

The Serbian swept the first set without conceding a break point and finished the job by claiming the last four games in the second despite Lazarov putting up more of a fight.

Elsewhere, Krajinovic's compatriot Miomir Kecmanovic crashed out to Italian Gianluca Mager, who fired down 11 aces and forced 10 break-point opportunities to earn an impressive 7-6 (7-3) 6-3 win.

Australian James Duckworth, meanwhile, had to launch a comeback before ultimately prevailing 3-6 6-4 6-4 against Finland's Emil Ruusuvuori to book a round two match with Benoit Paire.

The number one seed and defending champion Jannik Sinner will begin his campaign on Thursday with a last-16 contest against Egor Gerasimov.

Second seed Gael Monfils will play Ilya Ivashka, who defeated Pablo Andujar in straight sets, with the winner to face Mager, who is the first man in the quarter-finals.

Alex de Minaur will also be in action against American Marcos Giron.

Former world number one Andy Murray earned a second-round clash with Casper Ruud at the San Diego Open after easing past lucky loser Denis Kudla in straight sets.

Murray – a three-time grand slam champion – defeated Kudla 6-3 6-2 in just over an hour, winning an outstanding 28 of 31 (90 per cent) first-serve points on Tuesday.

The 34-year-old Murray was also on top on return, converting three of four break-point opportunities against Kudla, to complete a comprehensive display.

Murray – currently ranked 116th in the world – will face second seed Ruud next at the ATP 250 tournament.

Elsewhere, Grigor Dimitrov was made to work for his 6-3 1-6 7-5 victory over Hungarian Marton Fucsovics.

Former world number three Dimitrov triumphed in two hours, seven minutes, confirming a spot in the second round, where he will face US Open semi-finalist Felix Auger-Aliassime.

Diego Schwartzman – the sixth seed – progressed with a 6-2 6-3 win over Italian qualifier Federico Gaio.

Young American Sebastian Korda beat Tommy Paul 6-3 5-7 6-1 in more than two hours, while ninth seed Lorenzo Sonego, Cameron Norrie and Lloyd Harris were also victorious.

Marcos Giron moved through to the second round of the Sofia Open, but needed 10 match points to overcome Jaume Munar 6-7 (2-7) 6-1 6-4.

Giron lost the first set in a tie-break, however, the American fought back in an encounter lasting nearly three hours on Tuesday.

Twenty minutes of match time came in the final game, which encompassed all of Giron's match points.

Munar successfully staved off the first nine and had seven break points of his own. Yet his resistance was finally broken as Giron prevailed at the ATP Tour tournament.

Next up for Giron is a meeting with Australian third seed Alex de Minaur.

Eighth seed John Millman enjoyed a more routine 6-2 6-4 victory over Mikael Ymer, while there were also victories for Laslo Djere, Dimitar Kuzmanov and Egor Gerasimov.

Brandon Nakashima has been one of the ATP Tour's hottest players throughout the hardcourt season, and he kept rolling Monday before a hometown crowd. 

The 20-year-old Nakashima rallied to defeat Italian veteran Fabio Fognini 6-7(5), 6-1, 7-5 in the first round at the San Diego Open, setting up a second-round matchup with top seed Andrey Rublev. 

After qualifying for the main draw at Wimbledon earlier this summer, Nakashima reached finals at Los Cabos and Atlanta in successive weeks, falling to John Isner in the latter finale. He then knocked Isner out of the US Open in the first round in straight sets. 

Monday, he won 80 per cent of the points on his first serve, dialling up eight aces to just one for Fognini, who also double faulted 11 times. 

Another Southern California native, Taylor Fritz, also advanced Monday, beating qualifier Salvatore Caruso 6-4 7-6 (2) to earn a second-round meeting with fourth seed Denis Shapovalov.

It was a welcome reprieve for the world number 39, who had lost five of his previous six matches dating to a quarter-final win over Reilly Opelka in Atlanta. 

Earlier, world number 24 Aslan Karatsev opened the day's action by defeating Federico Delbonis 6-1 7-5. 

Benoit Paire is through to the second round of the Sofia Open following a 6-4 7-5 win over seventh seed Alejandro Davidovich Fokina. 

The Frenchman - ranked no. 49 in the world - marked his debut at the ATP 250 event by ending a three-match losing run, progressing after one hour and 37 minutes on court. 

Paire, who recorded five breaks of serve en route to victory, will be up against either James Duckworth or Emil Ruusuvuori next. 

"[I am] happy about the win," Paire said in his on-court interview. "It was not easy. Alejandro is a very good player, so I had to be focused on my game. 

"I had to serve well and do my best and that is what I did and I am very happy and proud of my game today.  

"I played well in the first game, it was good for my confidence. The most important thing is to stay on my game and stay focused. I was solid today so I am very happy." 

Also in Monday's action, Adrian Mannarino was another seed to suffer an early exit, going down in straight sets to Gianluca Mager. 

Miomir Kecmanovic came through a tight two-set contest to knock out Adrian Andreev, including taking the opener via a tie-break. 

Hubert Hurkacz collected his fourth ATP Tour title after defeating Pablo Carreno Busta in straight sets at the Moselle Open.

The Pole did not drop a set on his way to the final and produced yet another impressive outing to down Carreno Busta 7-6 (7-2) 6-3 in just 82 minutes.

Carreno Busta did, however, take an early lead and have Hurkacz reeling from a break down in the first set but the 24-year-old, who defeated former world number one Andy Murray this week, responded efficiently.

Having come from 3-1 down to 4-4, Hurkacz did not look back as his sharp first serve caused Carreno Busta all sorts of problems, most notably to secure the first-set tiebreaker with ease.

The pair continued to exchange breaks at the beginning of the second set but Hurkacz played well from the baseline and held serve to clinch his first trophy outside of the United States.

His victory means he holds a 4-0 record in ATP Tour finals and also saw him inflict revenge on Carreno Busta, who won the previous head-to-head clash in Cincinnati last month.

Hurkacz will be looking for doubles glory on Sunday as well, as he teams with international compatriot Jan Zielinski.

Kwon Soon-woo claimed his maiden ATP Tour title with a straight-sets defeat of James Duckworth at the Astana Open.

The South Korean came out on top in the battle of the unseeded first-time finalists on Sunday, winning 7-6 (8-6) 6-3 in Nur-Sultan.

Kwon won 86 per cent of points behind his first serve and came from behind in both sets to be crowned champion.

Australian Duckworth failed to convert three set points in a tie-break and Kwon made him pay, grasping his first opportunity to go a set up.

Kwon was broken in the first game of the second set, but the battling world number 82 hit straight back to draw level.

Duckworth, who had not dropped a set en route to the final, was broken again to trail 4-2 and he was unable to find a way back as the 23-year-old Kwon celebrated his finest hour.

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.

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.

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. 

Novak Djokovic was "playing for history" and suffered from nerves in his US Open final defeat to Daniil Medvedev, according to previous champion Dominic Thiem, who backed the 34-year-old to return "stronger than ever" in 2022.

Medvedev prevented Djokovic from becoming the first man since Rod Laver in 1969 to win all four grand slams in a single year, beating him 6-4 6-4 6-4 in Sunday's thrilling showpiece.

Djokovic was seen in tears during the third set as his hopes of adding the US Open to his run of wins at the Australian Open, French Open and Wimbledon this year slipped away.

But Thiem tipped Djokovic to bounce back from the disappointment of defeat and return in 2022 even stronger.

"One unbelievable goal slipped out of his hands yesterday," Thiem told Stats Perform.

"I expect him to be as strong as ever in 2022. I think after he won in Roland Garros, everybody was only talking about the calendar slam – first about the golden slam, and then about the calendar slam.

"He [Djokovic] was under pressure. Nobody can feel that or anything like that because of it being the calendar slam.

"I can feel it in a smaller way, probably from last year's final and from some other matches. And at some points it's just getting to you. And so, I really felt for him as well towards the end of the match.

"So, it can happen that it also makes him even stronger next year when all these talks and all this pressure is not that big anymore."

Thiem, who missed the tournament with a wrist injury that will rule him out until 2022, believes nerves were a factor in Djokovic's defeat but agreed with Medvedev's assessment of the Serbian as the greatest of all time – though he could not set him apart from Roger Federer and Rafael Nadal.

"For me, there are three GOATs in the game, and each of them has achieved something very unique," Thiem said of the trio locked on 20 major titles each.

"So it's still the same for me as it was before. The three of them are the best in the history to me.

"And I'm only super happy to be in the same era with them and to be able to compete with them. Hopefully many more times next year again."

Despite all appearances as he ploughed through the draws at all four grand slams this year, world number one Novak Djokovic does have a breaking point. 

Djokovic hit it on Sunday, falling 6-4 6-4 6-4 to Daniil Medvedev in the US Open final as the 20-time major champion finally proved unable to will himself out of an early hole. 

It was the fifth successive match in which Djokovic had dropped the opening set at Flushing Meadows, and the Serb superstar acknowledged afterward all of the energy he expended to get to the brink of the first men's calendar Grand Slam –since 1969 and a record 21st major title might finally have caught up with him. 

"Could be, could be [time spent on court a factor]. I had more hours on the court spent from Daniil, that's for sure," Djokovic said at his post-match news conference. "But was also emotionally very demanding period for me in the last five, six months. Slams and Olympics and playing at home in Belgrade.

"Everything was coming together for me here and kind of accumulating all the emotions that I've been through.

"Unfortunately I didn't make it in the final step. But when you draw a line, you have to be very satisfied with the year. Three wins, three slams and a final. For the last couple of years I've been very transparent and vocal about my goals, to play my best tennis at slams. I'm managing to do that.

"Of course, I was short today for another slam title, but I have to be proud with everything that my team and I have achieved. And in tennis we learn very quickly how to turn the next page.

"Very soon there are some more challenges, more things that are coming up. I have learned to overcome these kind of tough losses in the finals of slams, the ones that hurt the most."

This defeat sent a range of emotions surging through the emotional 34-year-old as he sat courtside while awaiting the trophy presentation. 

Asked what was going through his mind at that moment, Djokovic's initial answer was succinct. 

"Relief," he said. "I was glad it was over because the build up for this tournament and everything that mentally, emotionally I had to deal with throughout the tournament in the last couple of weeks was just a lot. It was a lot to handle.

"I was just glad that finally the run is over. At the same time I felt sadness, disappointment, and also gratitude for the crowd and for that special moment that they've created for me on the court."

Djokovic heaped praise on his opponent, saying he expects Medvedev to win more grand slams in the years ahead after the Russian broke through for his first.

That inevitably sparked thoughts of the coming generational change in the men's game, dominated for so long by Djokovic, Rafael Nadal (35) and Roger Federer (40).

With an astonishing 60 grand slam titles between them, their eventual departure from the stage will open up opportunities for Medvedev, Tokyo Olympics gold medallist Alexander Zverev and other younger players. 

Djokovic insisted he is not quite done yet, but he does believe that transition already is in progress. 

"The older guys are still hanging on," he said. "We're still trying to shine the light on the tennis world as much as we possibly can.

"I'm speaking on my own behalf. I still want to keep going, try to win more slams, play for my country. Those are the things that motivate me the most I think at this point.

"But the new generation, if you want to call them this way, is not anyone new. It's already current, established. Of course, they are going to take over.

"I think tennis is in good hands because they're all nice guys and very, very good, high-quality tennis players. They got something to offer on and off the court.

"We are hoping that the transition will be smooth in terms of the attention and the popularity of this sport. It's very important.

"We all, of course, want to win on the court, but at the same time we all at the top represent this sport. We need to be aware of that, take this responsibility and try to bring more fans to the world of tennis.

"At the end of the day that's what counts and that's what keeps our sport alive."

In Tokyo, it had been Alexander Zverev who denied Novak Djokovic his Olympic dream in a competition partially defined by controversy over the searing heat. In stifling temperatures inside Arthur Ashe Stadium on Sunday, the world number one saw his calendar Grand Slam hopes ended by a man often known for losing his cool.

Daniil Medvedev is among the most mercurial players on the ATP Tour. To watch Medvedev outwit his opponents when he is focused is one of the great joys of the modern game. When things go against him, though, his temper and his performance can unravel in a hurry.

To Djokovic's misfortune, in one of the biggest matches of his remarkable career, he came up against an inspired Medvedev enjoying obvious clarity of thought in a 6-4 6-4 6-4 win in the US Open final that means tennis' 'big three' remain locked on 20 grand slam titles apiece.

Medvedev is no stranger to heroics at tennis' largest stadium. Two years ago he enjoyed a rollercoaster journey in New York. Seeing red after being given a code violation for snatching a towel from a ballboy, Medvedev was mercilessly booed in a third-round match with Feliciano Lopez and openly goaded the fans thereafter in his on-court interview.

The booing continued in the subsequent round, but Medvedev's story that year was one of redemption, which ended with him receiving great credit for a remarkable near-comeback in a five-set epic final with Rafael Nadal.

Fast forward to a clash with another of the players firmly in the conversation for the best of all time and Medvedev sustained the levels he produced for two and a half sets against Nadal for three glorious sets as he ruthlessly took possession of a day that was supposed to belong to Djokovic.

Prior to the final, Djokovic had dropped the opening set in four of his previous matches at Flushing Meadows, winning three times in four sets and once in five.

As such, there was little reason not to expect a Djokovic comeback when Medvedev forged ahead in the showpiece.

However, in Medvedev, Djokovic found a foe completely unwilling to indulge his hopes of another recovery effort.

Coach Gilles Cervara labelled Medvedev a "genius" before the 2019 final and, when he plays as he did in clinching his first major title, it is tough to argue with that assessment.

As the elasticity of his movement enabled Medvedev to defend with an ease that belied the pressure of the occasion, Djokovic was simply unable to find a way through in the second set, which was decided with the artistry of the Russian's drop shot.

Djokovic could only hit into the tramlines having scurried in a desperate effort to meet such a shot, and that sense of desperation was evident when uncharacteristically poor play at the net from the Serbian gave Medvedev command in the third.

A pair of double faults played a role in Medvedev initially failing to serve out the match, the ice-cool focus escaping him for a brief moment, but there was to be no repeat when his second opportunity came as he finally clinched a maiden major on his third wedding anniversary.

So history denied. Not because of the heat, but because of a man keeping his cool in the face of the greatest challenge in the men's game and harnessing the genius that is now recognised by many more than just his coach. Extremely gracious in defeat, a potentially momentous day for Djokovic is now one he will want to forget. Instead, Medvedev and his wife have an anniversary to remember.