Serbia's Novak Djokovic's father Srdjan gestures during a press conference in Belgrade, Serbia, Monday, Jan. 10, 2022. Tennis star Novak Djokovic on Monday won a court battle to stay in Australia to contest the Australian Open despite being unvaccinated against COVID-19, but the government threatened to cancel his visa a second time. Federal Circuit Court Judge Anthony Kelly reinstated Djokovic's visa, which was canceled after his arrival last week because officials decided he didn't meet the criteria for an exemption to an entry requirement that all non-citizens be fully vaccinated. (AP Photo/Darko Vojinovic)

Serbia's Novak Djokovic's father Srdjan gestures during a press conference in Belgrade, Serbia, Monday, Jan. 10, 2022. Tennis star Novak Djokovic on Monday won a court battle to stay in Australia to contest the Australian Open despite being unvaccinated against COVID-19, but the government threatened to cancel his visa a second time. Federal Circuit Court Judge Anthony Kelly reinstated Djokovic's visa, which was canceled after his arrival last week because officials decided he didn't meet the criteria for an exemption to an entry requirement that all non-citizens be fully vaccinated. (AP Photo/Darko Vojinovic)