Tennis world number one Novak Djokovic mounted a legal challenge to being refused entry to Australia on Saturday (January 8).

Arguing he'd been given a medical exemption from vaccination because he'd been infected by COVID-19 last month.

Djokovic said in a court filing - ahead of a hearing on Monday over his visa cancellation - that he'd received the exemption from tournament organizer Tennis Australia, and a follow-up letter from the Department of Home Affairs saying he was allowed into the country.

The drama has has become a flashpoint for opponents of vaccine mandates around the world, as well as fuelling tensions between Serbia and Australia.

The Serbian player, hoping to win his 21st Grand Slam at the Australian Open later this month, is on his third day in immigration detention in Melbourne, in a case that has caused a sporting, political and diplomatic furore.

A vocal opponent of vaccine mandates, Djokovic has been confined since Thursday (January 6) in a modest hotel.