reporter: a far cry from his usual welcome, the world s number one stennis star is here until at least monday, when a court will decide if he can defend his title at the australian open or be deported. australia requires people to be fully vaccinated for covid-19 to enter the country or have a medical exemption, something djo djokovic s lawyers claim he has. border officials and the prime minister disagree. rules are rules. and there are no special cases. reporter: back home in serbia, djokovic s parents hail him as a national hero, being held captive. mr. djokovic is not being held captive in australia. he is afraid to leave at any time that he chooses to do so. reporter: fellow tennis stars are weighing in. nick cur yost tweeted, i got vaccinated because of others, and for my mum s health, but how we are handling novak s situation is bad, really bad.