World number one Novak Djokovic has been "playing by his own rules" and has put his bid for a 21st Grand Slam title at risk by not following Australia's COVID-19 vaccination requirements, world number four Stefanos Tsitsipas said on Thursday.
Images from Day 6 of the 2021 US Open in New York on Saturday.
Novak Djokovic won a record-equalling 20th Grand Slam title by after winning this year's Wimbledon drawing level with long-time rivals Roger Federer and Rafael Nadal.
Rafael Nadal is taking no pleasure from the absence of great rival Novak Djokovic at the Australian Open, even if it means he has a clearer shot at the Grand Slam title record.
Bidding for a record-extending ninth Australian Open title, the world number one and double-defending champion remains the runaway favourite at his favourite Grand Slam where he once remarked that he felt touched by the "divine".
World number one Novak Djokovic said on Wednesday he hopes rival Roger Federer will return to competitive action soon and be able to compete with the best again after the Swiss great said he would miss the Australian Open in January.
The 'Big Three' of men's tennis have found some "fresh energy" to thwart the charge of younger players on the tour, world number one Novak Djokovic said after setting up yet another title clash against his biggest rival against Rafael Nadal.
Alexander Zverev into ATP Finals semis after straight sets win over Carlos Alcaraz
'Is he serious? It's a selfish political move to gain popularity.'
So Djokovic will certainly not be letting his guard slip when he plays American Denis Kudla on Friday.
Second seed Daniil Medvedev will launch his bid to win his first major title against veteran Frenchman Richard Gasquet.
Novak Djokovic has suffered more than his fair share of heartache against Rafael Nadal at the French Open but Sunday's final offers him a chance to dethrone the claycourt king.
Djokovic announced on Tuesday he received an exemption to play in the Grand Slam tournament in Melbourne and said he was heading to Australia.
Djokovic has been even more visible on social media this week as the Tokyo Olympics got under way.
Carlos Alcaraz suffered a shock 6-1, 7-5 defeat against Norway's Casper Ruud in his opening match at the ATP Finals
Novak Djokovic blamed "human error" on Wednesday for a mistake in his Australian immigration paperwork and apologised for breaking isolation for a photoshoot when he had COVID-19 last month.
World men's tennis No. 1 Novak Djokovic headed reluctantly home on Monday after being kicked out of Australia because of his COVID-19 unvaccinated status, but the government left the door open for a possible return to his favourite Grand Slam in 2023.
Factbox on Carlos Alcaraz, who beat Alexander Zverev
Australian Open chief Craig Tiley is confident Rafael Nadal will be at Melbourne Park for next month's Grand Slam despite testing positive for COVID-19, but he is still uncertain whether Novak Djokovic will be playing.
The Serbian's 1-6, 6-3, 6-1 defeat also ended his dream of winning an Olympic singles gold medal, the only major honour missing from his long list of accolades.
Sinner, Alcaraz will keep tennis' flag flying: Shastri
Simona Halep questioned the "big difference" in how doping cases are treated after world number two Iga Swiatek was handed a one-month drugs ban
World number one Carlos Alcaraz retired injured against Holger Rune at the Paris Masters on Friday, sending his fellow 19-year-old through to the semi-finals, while Novak Djokovic and Felix Auger-Aliassime also sealed places in the last four.
Djokovic was disqualified while trailing Spaniard Pablo Carreno Busta 6-5 in the opening set of their fourth-round tie on Sunday, striking a line judge with a petulant swipe of the ball.
Djokovic practised his serves and returns with his entourage on an empty court at Melbourne Park
The 6-foot-5 frame of Matteo Berrettini will be standing in the way of Novak Djokovic's relentless pursuit of hoarding as many tennis milestones as possible when the two meet in a Wimbledon final where both men will be eyeing the record books.
IMAGES from Day 5 of the Wimbledon Championships at All England Lawn Tennis and Croquet Club on Friday.
Novak Djokovic could be barred from playing in the French Open as things stand now after the Sports Ministry said on Monday there would be no exemption from France's new vaccine pass law.
Novak Djokovic said he expects a "great battle" against Italian powerhouse Matteo Berrettini in Sunday's Wimbledon final when victory will earn the Serb a record-equalling 20th Grand Slam title.
Some 25,000-30,000 fans will be admitted to Melbourne Park on each day of the Grand Slam and Novak Djokovic got a taste of what was to come when he played an exhibition match in Adelaide after coming out of quarantine on Friday.
Novak Djokovic's loss in the US Open final on Sunday denied him a calendar-year Grand Slam but the Serbian world number one said he was just happy his chase for perfection was finally over.
Rafael Nadal said he feels sorry for Novak Djokovic after the world number one was denied entry into Australia but added that the Serb knew for months he could potentially face problems if he arrived without being vaccinated against COVID-19.
Daniil Medvedev dominated Canada's Felix Auger-Aliassime 6-4, 7-5, 6-2 on Friday to reach the US Open final courtesy of a dozen aces in just a little over two hours.
The world number one overcame a sluggish start to defeat Argentine Diego Schwartzman 7-5, 6-3 for a record 36th ATP Masters crown.
Novak Djokovic, who has won a record nine titles at Melbourne Park including the last three, has repeatedly declined to reveal whether he has been vaccinated against COVID-19, with Australian Open organisers Tennis Australia confirming that all players would have to be vaccinated to compete in Melbourne.
Alexander Zverev overcame late nerves to beat world number one Novak Djokovic on Saturday and set up a final showdown with Daniil Medvedev at the ATP Finals.
Zheng Qinwen became the first Chinese player to win an Olympic tennis singles gold medal when she held off Croatia's Donna Vekic for a 6-2, 6-3 win in a tense final on Saturday.
Djokovic's father blamed the cancellation of the tour on Dimitrov. There is nothing to suggest that Dimitrov spread the virus to others.
Next up for the 35-year-old will be another American in 39th-ranked Tommy Paul with a potential semi-final clash against top-seeded Russian Daniil Medvedev, who he defeated in the Australian Open final from a two-sets deficit.
