MELBOURNE (REUTERS) - World No. 1 Novak Djokovic pulled out of an Adelaide exhibition because of a blistered hand on Friday (Jan 29) before appearing on court to play a set after all, helping his compatriot Filip Krajinovic beat Jannik Sinner.

Djokovic was scheduled to kick off the "Day at the Drive" event in front of a crowd of 4,000 at Adelaide's Memorial Drive Tennis Club but pulled out minutes before he was due on court and replaced by his compatriot.

After his practice partner had won the first set, however, Djokovic bounded into the arena and proceeded to wrap up a 6-3, 6-3 win over the Italian teenager.

"I'm sorry that I didn't step in on the court from the beginning," said Djokovic, who was celebrating his first day of freedom after 14 days in quarantine.

"I had to do some treatment with my physio, I wasn't feeling my best for the last two days and I didn't know how I was going to react."

Djokovic looked to be largely unhindered by the nasty-looking blister on the palm of his right hand.

"It's not easy but it's part of what we do, we're professional athletes, we learn over the years to play with the pain," he added.

"It's just a case of whether that pain is bearable or not. Obviously, coming off a hard training block and having the ATP Cup and Australian Open coming up you don't want to risk it too much."

Former Grand Slam doubles champion John Fitzgerald had said on Channel Nine TV that the Serb had withdrawn because of a blistered hand, which would not impact his bid for a ninth Australian Open title at Melbourne Park from Feb 8.

Djokovic earlier told reporters he had taken a walk in a park to celebrate his release from the 14 days of quarantine players coming from overseas were obliged to undergo to play in Australia.

Djokovic and Krajinovic will join forces again in the Serbia team defending the ATP Cup in Melbourne next week before the year's opening Grand Slam.

Serena Williams beat Naomi Osaka 6-2, 2-6, 10-7 in a 'super breaker' in the second match, with both players united in their excitement at playing in front of fans.

"We haven't played in front of a crowd in over a year so it's been a really long time," said Williams, who has been isolating with her three-year-old daughter.

Venus Williams, Naomi Osaka, Rafael Nadal, Dominic Thiem, Ashleigh Barty and Simona Halep were all scheduled to play later matches.

They were among a select group of players who underwent lockdown in Adelaide rather than Melbourne.

"We just can say thank you very much to South Australia and for all the unbelievable great work that Tennis Australia has been doing to allow us to play this tournament," Nadal told reporters, summing up sentiments expressed by all the players.

Djokovic, who last week drew heavy criticism after he sent a letter to organisers asking for changes to the quarantine rules, said conditions were "great for us, considering the circumstances".

The players have been allowed out to practise for five hours a day during their quarantine but Djokovic said he had headed to a local park on his first morning in Australia without restrictions.

"Just putting your feet on the ground, you know, just doing something that I didn't have a chance to do," the Serb said.

"Just having the space, I think, that's what we all kind of missed."

Serena's quarantine had an extra wrinkle in the shape of her daughter and they celebrated their release with a trip to Adelaide Zoo.

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

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

Williams will be bidding for her 24th Grand Slam title at Melbourne Park, which would tie her with Australian Margaret Court as the most successful player of all time.

"It's good to always have goals that you try to reach and kind of see what happens," Williams said.