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.
Djokovic practised his serves and returns with his entourage on an empty court at Melbourne Park
The Australian government cancelled Novak Djokovic's visa for a second time on Friday, saying the World No 1, unvaccinated for COVID-19, may pose a risk to the community.