Serena Williams took her daughter to the zoo and Novak Djokovic walked barefoot in a park as the stars of tennis emerged from a fortnight of quarantine ahead of the coronavirus-delayed Australian Open Friday.

More than 1,000 players, coaches and officials jetted into largely virus-free Australia this month for 14 days' lockdown ahead of the opening Grand Slam of the year, with most allowed out for just five hours of daily supervised training.

Naomi Osaka posed for selfies as she emerged from quarantine in Adelaide
Naomi Osaka posed for selfies as she emerged from quarantine in Adelaide AFP / Brenton EDWARDS

Big guns Williams, Djokovic, Rafael Nadal and Naomi Osaka were among a select group that served their time in Adelaide rather than Melbourne ahead of an exhibition in the southern city on Friday.

Seven-time Australian Open winner Williams, who is gunning for one more Slam title to equal Margaret Court's record of 24 at next month's tournament, spent her two weeks holed up with three-year-old daughter Olympia.

"I'm so glad the quarantine is over because to be in a room with a three-year-old and being her best friend is definitely difficult, especially after training and working out and then it's like, oh my gosh, it never ends," said Williams.

Men's tennis world number one Novak Djokovic played with an Australian Rules football after his two-week quarantine in Adelaide
Men's tennis world number one Novak Djokovic played with an Australian Rules football after his two-week quarantine in Adelaide AFP / Brenton EDWARDS

"But it was fun... honestly I wouldn't trade anything for spending hours with her."

Asked what she did on her first day of freedom, Williams said they headed to the zoo.

"We had a calendar in our room and every day we marked an x on the days that went by and a big circle on the quarantine ending day, and we promised that we would take her to the zoo to see koalas and kangaroos," said the American.

(L-R) Djokovic, Rafael Nadal and Osaka played an exhibition event in Adelaide
(L-R) Djokovic, Rafael Nadal and Osaka played an exhibition event in Adelaide AFP / Michael Errey

She later played her first match of the season, with Olympia among a packed crowd at Memorial Drive, beating a sometimes-erratic world number three Osaka 6-2, 2-6 (10/7).

"I haven't seen people in -- it feels like forever," Osaka told the crowd.

Australia's world number one Ashleigh Barty was due to face second-ranked Simona Halep later.

Serena Williams (C) completed two weeks' quarantine in Adelaide
Serena Williams (C) completed two weeks' quarantine in Adelaide AFP / Michael Errey

Aggressive restrictions on incoming travel have helped keep the coronavirus at bay in Australia, making it one of the countries that is still able to have fans at sports events.

With thousands of Australians stranded abroad, the players' arrival prompted some disquiet among the public, especially when some complained about their quarantine and cases sprang up among the travelling party.

Djokovic only played one of his two scheduled sets against Jannik Sinner due to a large blister on his right hand, winning 6-3 in his first competitive game of the year.

"We didn't play in front of this big a crowd in 12 months so this is something very special," he said, having earlier opted for a quiet walk to celebrate finishing quarantine.

"You know, just putting bare feet on the ground, just doing something that I didn't have a chance to do so, just having the space I think that's what we all kind of missed," the 17-time Grand Slam winner said.

Spanish great Nadal, who is aiming for a record-breaking 21st Slam title in Melbourne, moving him past the injured Roger Federer, plays third-ranked Dominic Thiem in his exhibition clash.

He said it had been difficult to think about tennis for much of 2020 due to the coronavirus pandemic, but added: "Here we are, starting another year... I'm excited to be back."

While most players have been able to train, 72 were confined to their Melbourne hotel rooms 24 hours a day, after eight positive Covid-19 cases were detected on their charter flights to Australia.

They and other players in Melbourne also began tasting freedom, but persistent rain greeted them rather than the sunshine in Adelaide.

Six ATP and WTA tournaments will take place at Melbourne Park next week before the Australian Open, delayed three weeks over coronavirus complications, starts on February 8.