Top seed Dominic Thiem was knocked out the Rio Open in the first round on Tuesday, going down 6-3, 6-3 to Laslo Djere.
Wimbledon champion Garbine Muguruza notched up her first ever victory on Arthur Ashe Stadium with a 6-0, 6-3 win over American Varvara Lepchenko at the US Open on Monday.
Kyle Edmund has the most destructive forehand in tennis and it can power him into the world's top 10, according to three-times Australian Open champion Mats Wilander.
The players have been allowed out to practise for five hours a day during their quarantine but Djokovic said he had headed to a local park on his first morning in Australia without restrictions.
Images from Day 3 of the Australian Open in Melbourne on Wednesday
Images from Day 4 of the Wimbledon tennis championships played in London, on Wednesday.
Images from Day 3 of the French Open matches played at Roland Garros on Tuesday
IMAGES from the matches played on Day 2 of the Wimbledon Lawn Tennis Championships at All England Lawn Tennis and Croquet Club on Tuesday.
Former world number one Garbine Muguruza was beaten 7-5, 6-4 by Aryna Sabalenka in the China Open second round on Tuesday while an ailing Jelena Ostapenko lost 6-0, 6-0 to Wang Qiang.
In fact, barring 2014 when Stan Wawrinka won the title, no player apart from the quartet has even been involved in the men's final at Melbourne Park since 2008.
Federer welcomed the emergence of new challengers
It took the COVID-19 pandemic to put a brake on Djokovic's 18-match unbeaten run in 2020, as he won the ATP Cup with Serbia, an eighth Australian Open title and a fifth Dubai Tennis Championships before the season came to a halt in early March.
Exodus of big guns opens up bottom half of men's draw
US Open, the final Grand Slam of the season, starts Monday, August 28, at Flushing Meadows in New York.
A summary of sports events and sports persons, who made news on Sunday
World number one Novak Djokovic turned the page on his contentious US Open exit and began his claycourt season with a convincing 6-3, 6-2 victory over wildcard Salvatore Caruso in the second round of the Italian Open.
Images from Day 9 of the 2020 Australian Open in Melbourne on Tuesday.
Summary of sports events and persons who made news on Wednesday
Images from Day 4 of the US Open in New York on Thursday.
Summary of sports events and persons who made news on Monday
Djokovic, who has ruled like no other on Rod Laver Arena simply had no answer as Chung, nine years his junior, wore him into the ground to win.
Images from matches played on Day 4 of the Australian Open at Melbourne Park on Thursday
Will it be Rafa versus Djoko in Sunday's final?
Images from Day 6 of the US Open in New York, on Saturday.
Images from Day 2 of the Wimbledon tennis championships in London, on Tuesday.
Images from the second day at the US Open, the final Grand Slam tournament of the year.
Images from Sunday's action at the Australian Open in Melbourne.
Summary of sports events and persons who made news on Sunday
Images from the matches played at the All England Lawn Tennis and Croquet Club, in Wimbledon, London, on Monday.
Summary of sports events and persons who made news on Wednesday
IMAGES of the all the action from Day 2 of the Australian Open played at Melbourne Park on Tuesday