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".
Djokovic will be nowhere near the centre court after losing his bid to overturn a second visa cancellation.
Third seed Rafael Nadal remains on course for a 10th Barcelona Open title, advancing to the quarter finals with a routine 6-3, 6-4 victory over Kevin Anderson.
The Serbian second seed will now play Austrian Dominic Thiem, who shocked seven times winner Rafa Nadal on Friday but has lost his previous four encounters with Djokovic, in the evening semi-final.
Novak Djokovic has pulled out of the Serbia team for the ATP Cup in Sydney, event organisers said on Wednesday, raising further doubts over whether the world number one will defend his Australian Open title next month.
Earlier in the day, Croatia's Borna Coric said he has tested positive for coronavirus. He became the second player to test positive for COVID-19 after Bulgaria's Grigor Dimitrov.
Nadal's great rival and fellow 20-times Grand Slam winner Roger Federer is also out of the US Open and will be sidelined for many months because he needs knee surgery.
An inspired Milos Raonic toppled Roger Federer 6-4, 6-4 to win the Brisbane International on Sunday and avenge his defeat to the Swiss master in last year's final.
Stan Wawrinka outlasted Frances Tiafoe over three sets to set up an all-home quarter-final against compatriot and fellow veteran Roger Federer at the Swiss Indoors on Thursday. The 34-year-old Waewrinka, who won 6-3, 3-6, 7-5, will attempt to beat Federer for only the fourth time when they meet for their 27th clash on Friday in a dream tie for the Basel crowd.
Victoria Azarenka, 31, won a bronze medal for Belarus in singles and a gold in mixed doubles at the 2012 Summer Games in London. Angelique Kerber, 33, won the silver in singles for Germany at the 2016 Olympics in Rio de Janeiro.
Djokovic said he was '50-50' about competing at the Tokyo Olympics
No sooner had Novak Djokovic claimed his 17th Grand Slam trophy by triumphing at the Australian Open for the eighth time on Sunday, the Serb was already setting himself a deadline to claim the record of major titles. Djokovic's 6-4, 4-6, 2-6, 6-3, 6-4 victory in a thriller over fifth seed Dominic Thiem drew him within three slams of Roger Federer's haul of 20 and two behind second-placed Rafa Nadal's 19.
The latest tennis rankings have been announced by the ATP and WTA
Kate Middleton, the Duchess of Cambridge, arrived for the first day of Wimbledon on Monday with a dramatic new hairstyle to watch Andy Murray play his opening match.
Djokovic, Coric, Grigor Dimitrov and Viktor Troicki all tested positive for COVID-19 after playing in the event in Serbia and Croatia, which drew big crowds and saw the players pose for pictures together.
Nadal, Djokovic, Murray, Wawrinka all will be in action at Roland Garros on Wednesday
Andy Murray and Emma Raducanu clinched hard-fought wins in their first round matches at Indian Wells.
Top seed Roger Federer dispatched Greek third seed Stefanos Tsitsipas 6-4, 6-4 in the semi-finals of the Swiss Indoors championships in Basel.
Indian Davis Cupper Prajnesh Gunnewaran, on Wednesday, earned the biggest win of his career by stunning world number 23 Denis Shapovalov in the opening round of the ATP Mercedes Cup in Stuttgart.
Penpix of the top men's contenders at the 2021 French Open which begins on Sunday:
The 12-time French Open champion unhappy with schedule.
Having dug in early on to stay with Federer, Nishikori ended up running away with the match to inflict a first straight sets defeat in the ATP Finals round-robin stages on the 20-time Grand Slam champion.
'During the grass court season, I unfortunately experienced a setback with my knee, and have accepted that I must withdraw from the Tokyo Olympic Games.'
The three-time major winner would be given a protected ranking of number two, the Australian Open organisers said
Images from Day 10 of the 2020 French Open, at Roland Garros, in Paris.
The major milestones in Djokovic's career
World number one Novak Djokovic was disqualified from his US Open fourth round match against Pablo Carreno Busta on Sunday after the Serbian struck a line judge with a ball following a point.
Austria's Dominic Thiem strained every sinew trying to cling on to the 32-year-old Spaniard and at times even gained a precarious foothold in his first Grand Slam final.
Not since Stan Wawrinka's 2016 US Open triumph has a Grand Slam been won by someone other than the 'Big Three', winners of the last 13 major titles.
The 32-year-old debutant at the ATP's blue riband event won the first 11 games of the round-robin clash before a relieved Nishikori finally got on the scoreboard with an angled winner.
was on a 21-match unbeaten run before the season came to a halt in early March, winning the ATP Cup with Serbia, an eighth Australian Open title and a fifth Dubai Tennis Championships crown.
Halep said she would not recover from a calf injury in time, Wawrinka underwent foot surgery that would rule him out of the Games
The world No 1 is certainly buoyed by the prospect of emulating his achievement of holding all four majors but knows that nothing less than perfection will be required.
Masks were required and high-fives banned, with signs reminding those in attendance to maintain proper social distancing.
A summary of sports events and persons who made news on Friday
German Alexander Zverev says he cannot rest on his laurels after beating Novak Djokovic to win the Italian Open on Sunday and has set his sights on bigger titles in order to retain his place in the world's top 10.
The Briton, who was thrashed 6-3 6-1 by the Croatian in the Dubai Championships in 2015, performed poorly in the first set and after recovering in the second he then surrendered his serve in the seventh game, giving Coric three break points.
Raducanu stormed into the third round of the Cincinnati Open