The clock is ticking on Novak Djokovic's prospects of playing at the US Open, two days out from the draw at Flushing Meadows.

Wimbledon champion Djokovic, who lost to Daniil Medvedev in last year's final in New York, has his route to the United States blocked by red tape at present.

US authorities are refusing to allow unvaccinated foreign visitors to enter the country, and barring a change of policy on that front, his hopes appear forlorn. Djokovic, a three-time US Open champion, has refused to accept any COVID-19 vaccine.

The United States Tennis Association (USTA) has pledged to adhere to government rulings surrounding coronavirus protocols, despite including Djokovic on the US Open entry list last month.

He remains on that list for now, but there was an indication that the US Open may not be expecting to see Djokovic when a promotional poster was revealed this week that featured four top women players and four leading men.

The men selected were defending champion Medvedev, 22-time grand slam winner Rafael Nadal, Australian Nick Kyrgios and Spanish teenager Carlos Alcaraz. All were archive pictures, so Djokovic could easily have been selected for the advertising campaign.

His exclusion prompted an angry response on social media from some fans of the 35-year-old Serbian, with one saying it would be "a failed tournament if he doesn't participate in it".

The US Open draws are due to take place on Thursday ahead of the start of the tournament on Monday.

Leading players are already assembling on site, with Medvedev, Serena Williams, Nadal, Alcaraz, Simona Halep and Andy Murray among those with practice sessions booked in for Tuesday.

For Djokovic to be allowed into the United States, it appears he would require a sudden change of entry rules from law-makers, or he would have to be considered suitable for an exemption.

In late July, he said he was "preparing as if I will be allowed to compete"; however, he has not been able to travel for the build-up tournaments.

On Instagram, Djokovic's last tennis-related post came on Monday night as he sent a congratulatory message to shock Cincinnati champion Borna Coric, telling the Croatian: "Bravo king! Totally deserved. All the effort and patience paid off. Go ahead and good luck."

Djokovic was not allowed to play at the Australian Open at the start of the year, when issues surrounding his visa ended with him being deported from Melbourne on public health grounds due to not taking the vaccine.

American great John McEnroe told Tennis 365 in July it was "crazy" that Djokovic should have to miss the US Open and called for a solution to be found.

The current entry rules in the United States were not in place when Djokovic was toppled by Medvedev in last year's men's singles final, ending his hopes of a calendar Grand Slam.

World number two Alexander Zverev has withdrawn from the US Open as he recovers from ankle surgery.

The German went under the knife after tearing all three of the lateral ligaments in his right ankle during his French Open semi-final against Rafael Nadal.

Zverev will not make his comeback at the final grand slam of the year in New York, as his withdrawal was announced on Monday.

The 25-year-old reached his only major final at Flushing Meadows two years ago, losing to Dominic Thiem.

Zverev stated after his operation that surgery was "the best choice" to ensure his ligaments heal properly and he could return to competition "as quickly as possible."

The US Open gets under way next Monday, with doubts remaining over whether Novak Djokovic will be able to play due to the 21-time grand slam champion opting against receiving a coronavirus vaccine.

The prize pot for this year's US Open will top $60million for the first time in the competition's history, event organisers have announced.

The 2022 edition at Flushing Meadows gets under way on August 29 and runs for just under two weeks.

It was revealed on Thursday that $60m will be up for grabs, topping the previous record of $57.5m from last year, with both singles champions to receive $2.6m.

Players will be given $80,000 for making the main draw and $121,000 should they make it to the second round. Runners-up in the singles will pocket $1.3m.

In the doubles, the champions will receive $688,000, the runners-up $344,000 and the semi-finalists $172,000.

Pablo Carreno-Busta came back from a set down to mount a superb comeback against Hubert Hurkacz and win the first ATP 1000 event of his career on Sunday.

The Spaniard became the first unseeded player to win the tournament since Guilhermo Canas in 2002 after weathering an early storm to shock the eighth seed 3-6 6-3 6-3 in Montreal.

Having come through a gruelling semi-final encounter with Dan Evans to reach his first ATP 1000 final in singles, the Tokyo 2020 bronze medallist struggled to deal with his opponent's impressive slew of aces in the first set, and saw his serve broken in the sixth game.

But a ruthless start to the second set saw Carreno-Busta break early, racing out to a 3-0 lead and holding his nerve to keep the gap to his Polish opponent, who was chasing a second ATP 1000 crown.

World number 10 Hurkacz attempted to rally with a fine start to the third set, but another loss of serve effectively stalled his momentum and Carreno-Busta was able to take the victory.

The result marks a much-needed boost for Carreno-Busta, who suffered first-round exits at the French Open and Wimbledon after making the last-16 in Australia, with the U.S. Open set to start later this month.

Hubert Hurkacz will contest the second ATP 1000 final of his career after coming from a set behind to defeat world number five Casper Ruud 5-7 6-3 6-2 in the semi-final of the Canadian Open on Saturday.

It was an interesting clash of styles going into the contest, with Hurkacz expected to rely on his dominant serve, while Ruud is one of the game's top returners, so when Ruud responded to an early break and was the one serving up a storm, it spelled trouble for the world number 10.

Ruud landed 78 per cent of his first serves in the opening set, compared to 60 per cent for Hurkacz, and the Norwegian won 95 per cent of those points (20-of-21) to allow just one break point in the frame while creating four for himself.

As Ruud's serve began to falter – with his first serve accuracy and effectiveness both cratering in the second and third set – his game began to struggle to hold up to the metronomic consistency of Hurkacz, who won the ace count 18-to-eight.

After pulling the match even at one set each, Hurkacz took the contest by the scruff of the neck and won the first four games of the deciding frame to pull away.

Poland's Hurkacz – who won his only previous ATP 1000 final against Jannik Sinner at the 2021 Miami Open – will now face Pablo Carreno-Busta in the decider after the Spaniard prevailed in a three-hour war of attrition against Daniel Evans 7-5 6-7 (7-9) 6-2.

In a match that was close in every area, Carreno-Busta was slightly better, winning 68 per cent (68-of-100) of his service points compared to 60 per cent (66-of-110) for Evans, while committing just one double fault compared to the Englishman's six.

It will be Carreno-Busta's first ATP 1000 final appearance, with the 2021 Hamburg Open – an ATP 500 event – the only career title for the 31-year-old above the ATP 250 level.

Nick Kyrgios' red-hot form has been halted after going down in three sets to eighth seed Hubert Hurkacz in the quarter-finals of the Canadian Open on Friday.

Hurkacz ran away with victory, triumphing 7-6 (7-4) 6-7 (5-7) 6-1 in one hour and 46 minutes in Montreal.

Wimbledon finalist Kyrgios had come into the encounter fresh from winning 15 of his past 16 matches, including lifting the title at last week's Washington Open. Kyrgios' run had fueled expectations around him at the upcoming US Open.

"Nick has been playing some incredible tennis throughout the past weeks, so it is a pleasure playing against him," Hurkacz said post-match in his on-court interview.

"I started really well. Nick was maybe a little bit injured, which might have hurt his serve. With both of us serving so well, that few per cent can make the difference."

Kyrgios was quick on serve but the 25-year-old Pole eventually ground him down, prevailing in the third set aided by an early break.

That break came after Kyrgios gave up two double faults, leading to the Australian to complain to the umpire about his opponent's mid-match break for a change of clothes.

The Australian was unable to break Hurkacz's serve throughout the match, with the Pole edging the aces count 20-19, while he was also superior on return. Kyrgios had more winners (55-47), but more unforced errors (24-13).

Hurkacz, who will face fourth seed Casper Ruud in the semi-finals, is the only former Masters 1000 champion left in the draw.

Ruud cruised into the last four with a 6-1 6-2 victory over hometown hero Felix Auger-Aliassime who was brushed aside in one hour and 14 minutes.

The Norwegian's win marks his third ATP Masters 1000 semi-final of the season, with the Canadian plagued by 21 unforced errors compared to Ruud's eight.

Unseeded Briton Daniel Evans fought back from a lopsided opening set to knock off Tommy Paul 1-6 6-3 6-4.

Evans will face Spaniard Pablo Carreno Busta after he defeated Jack Draper 7-6 (7-4) 6-1 in just under two hours.

Australia's Nick Kyrgios has now won 15 of his past 16 matches after defeating compatriot Alex de Minaur 6-2 6-3 in the third round of the Canadian Open – with his only loss coming in the Wimbledon final against Novak Djokovic.

Fresh off his first singles title since 2019 when he won last week's Washington Open, Kyrgios collected his ninth consecutive victory in impressive fashion, showing no difficulty in navigating his first-ever matchup against his fellow countryman.

He won the first four games of the match, and snatched a break in the first game of the second set to book his quarter-final against Poland's Hubert Hurkacz.

Hurkacz, the eighth seed, had to come back from a set down to defeat Spain's Albert Ramos-Vinolas 6-7 (6-8) 6-2 7-6 (7-3). He struggled with his serve early, with four double faults in the opening frame, but cleaned it up as the match went on, double-faulting only once in the last two sets.

England's top hope Cameron Norrie suffered a disappointing 6-3 6-4 defeat at the hands of world number nine Felix Auger-Aliassime, but Daniel Evans and Jack Draper made it through to fly the flag.

Evans pulled off an upset win to beat 10th seed Taylor Fritz 7-6 (7-5) 1-6 7-5, and 20-year-old Draper was up a set when 17th seed Gael Monfils retired with an injury at 6-2 0-2.

American Tommy Paul claimed another scalp with his 6-4 6-2 victory against 13th seed Marin Cilic, giving him back-to-back wins against top-15 opponents after emerging triumphant against Carlos Alcaraz in the previous round.

In the final match of the day, Pablo Carreno-Busta beat his third top-30 opponent of the week with a 6-2 6-4 result against Italy's Jannik Sinner, following strong successes against Matteo Berrettini and Holger Rune.

Nick Kyrgios set up a mouth-watering second-round showdown against world number one Daniil Medvedev after defeating Argentina's Sebastian Baez 6-4 6-4 in his opening match of the Canadian Open on Tuesday.

The in-form Kyrgios is coming off his first ATP singles title since 2019 after winning the Washington Open this past week, where he also won the doubles partnered with Jack Sock. 

Against Baez, he served all six of the match's aces to make it through unscathed, and he will now play the top-ranked Russian – who Kyrgios has beaten twice – although he dropped their third meeting at the Australian Open this year.

Dating back to the start of his Wimbledon run, where Kyrgios made his first grand slam final, the Australian has now won 13 of his past 14 matches, with the only loss coming in the Wimbledon final to Novak Djokovic.

Earlier on, 11th seed Matteo Berrettini was the first upset of the day as he went down 6-3 6-2 against Spain's Pablo Carreno-Busta, while fellow Spaniard Pedro Martinez had less success, getting bounced by France's Gael Monfils 7-6 (7-4) 3-6 6-2.

America's Tommy Paul delivered a gut-punch to his neighbours in the Great White North by eliminating Canada's own Vasek Pospisil 6-4 6-4, and his Canadian compatriot Alexis Galarneau also struggled in his 6-4 7-5 loss to Bulgaria's Grigor Dimitrov.

Marin Cilic showed why he is the 13th seed with a strong 6-3 6-2 win in his all-Croatian battle against Borna Coric, and American Maxim Cressy had similar success against Russia's Aslan Karatsev 6-4 6-4.

In a battle of the French it was Adrian Mannarino prevailing 6-3 6-3 against Arthur Rinderknech, and a pair of Englishmen made their way through unscathed as Daniel Evans won a back-and-forth contest against Filip Krajinovic 6-2 1-6 6-0, while Jack Draper returned to his rain-interrupted fixture against Hugo Gaston to finish the job 6-2 6-3.

Alex de Minaur ensured it would be a grim day for the Canadian fans as he eliminated Denis Shapovalov 7-5 7-6 (7-4), before Holger Rune fought off the challenge of Fabio Fognini to emerge a 6-3 7-5 winner.

In the late session, Roberto Bautista-Agut defeated Marcos Giron 7-6 (7-5) 6-3, ninth seed Cameron Norrie needed just over an hour for his straight sets 6-4 6-4 win over Brandon Nakashima, and Andy Murray had no answer for Taylor Fritz as he went down 6-1 6-3.

Yoshihito Nishioka's strong form held up after his runner-up finish at the Washington Open, cruising past Benoit Paire 6-2 6-3, while 25-year-old Botic van de Zanschulp continued his rise up the rankings with a 6-1 7-5 victory over Miomir Kecmanovic.

12th seed Diego Schwartzman needed three sets to navigate the challenge of Alejandro Davidovich Fokina 1-6 6-3 6-4, and Albert Ramos-Vinolas got the better of Belgium's David Goffin 7-6 (7-2) 6-2.

In the final match of the night, world number 10 Hubert Hurkacz responded to adversity in the second set to pull out a 6-3 6-7 (4-7) 6-2 win against Finland's Emil Ruusuvuori.