The 38-year-old Swiss national said he needed follow-up arthroscopic surgery after undergoing a similar procedure in February.
Roger Federer becomes the first player from his sport atop the annual list since its 1990 debut, rising from fifth in 2019.
All professional tennis tours were suspended in early March and will not return before August as countries went into lockdowns and closed borders to contain the spread of the novel coronavirus.
The current world number one, Novak Djokovic has 17 Grand Slam titles to his name - two behind Rafael Nadal and three fewer than Roger Federer.
To the delight of fans, happy to discover some hidden facets of their idols, stars from Karim Benzema to the Brazilian legend Ronaldo and even Rafael Nadal, are dropping their habitual discretion to interact live with their millions of followers.
Many countries are sending aid and emergency workers to those in greatest need, as a spirit of cooperation takes hold internationally.
Novak Djokovic admits he was on brink of defeat with dizziness and dehydration before coming through a five-set thriller against Dominic Thiem to clinch title – also his 17th Grand Slam – and return to world number one.
Nobody beats Novak Djokovic at this stage of the Australian Open. At least, not until now. Djokovic is a seven-time champion at Melbourne Park, where he has never lost a final or semifinal he has contested.
The 38-year-old swatted aside Steve Johnson 6-3, 6-2, 6-2 to race into the second round, kickstarting his bid for a 21st Grand Slam title in immaculate style.
Novak Djokovic and Rafael Nadal urged organisers of the ATP Cup and Davis Cup Finals to consider a possible merger, saying it makes little sense to have two men’s team competitions on the tennis calendar.
After a 7-5, 7-5 defeat to Dominic Thiem in his tournament opener, six-time champion Roger Federer may find it tricky to qualify for the last four of the ATP Finals.
The British parliamentarian became famous for his eloquence, his loud ties and allowing Remain-leading politicians to table emergency debates about Brexit. Now he has left, will British politics ever be the same again?
Subscribe to our Youtube channel for all latest in-depth, on the ground reporting from around the world.
Copyright © 2020 TRT World.