Sporting a peroxide blond hairstyle, the new-look Tomic dished up his usual antics on Melbourne's Kia Arena in a speedy 6-1 6-4 first-loss to rising star Roman Safiullin.

Tomic lasted just 57 minutes against the match-hardened Russian before later vowing to his Instagram followers "to do better next time".

"Feeling really sick. I'm back in my hotel room now," Tomic posted.

"Just spoke to the doctor on site and they've asked me to isolate. They couldn't treat me yet to avoid contact."

Trailing 1-2 in the second set, Tomic told umpire Aline Da Rocha Nocinto at the change-over he thought he had the virus.

"I'm sure in the next two days I will test positive, I'm telling you," the 29-year-old said from his chair.

"I'll buy you dinner if I don't test positive in three days, otherwise you buy me dinner (to the umpire)."

Tomic told her he couldn't believe there was no official PCR testing for players.

"They're allowing players to come on court with rapid tests in their room, c'mon ... no official PCR testing," he said.

Fellow Australian Nick Kyrgios had to withdraw from the Sydney Tennis Classic after he contracted COVID-19.

A lethargic Tomic was seen by the trainer at the first changeover in the opening set and was seen taking his pulse while out on court.

The former Wimbledon quarter-finalist was broken in fourth game and quickly capitulated, losing the first set in just 23 minutes.

Tomic rallied in the second but Safiullin, who was an unlikely star in Russia's run to the ATP Cup semi-finals last week, had his measure.

Oblivious to his opponent's virus claims, Safiullin offered a fist bump after match point, which Tomic accepted.

The Australian was unable to attend a post-match media conference to explain his insipid performance with organisers taking a cautious approach after his COVID-19 comments.

"Very disapppointed as I really wanted to make Aussies proud and perform well on my home turf."

Since becoming the youngest player, at 16 in 2009, to win a men's main-draw match at the Open, Tomic has made the second week three times and reached the third round on four other occasions.

He was the only Australian out of 20 hopefuls to successfully make the Open main draw last year when the men's qualifying event was held in Doha.

But the one world No.17, now ranked 260, hasn't won a set since a first-round qualifying victory at Wimbledon last June.

Despite arriving in Melbourne vowing to climb the rankings, Tomic will tumble even further after failing to back up his run to last year's Australian Open second round.

While Tomic crashed out, 17-year-old Edward Winter scored the biggest win of his career, upsetting former world No.6 Gilles Simon 6-3 1-6 6-3.

Marc Polmans, Matt Ebden plus Zoe Hives, Taylah Preston, Seone Mendez, Lizette Cabrera, Jaimee Fourlis and Arina Rodionova in women's qualifying also advanced.

But Akira Santillan, Andrew Harris, Tristan Schoolkate, Destanee Aiava, Talia Gibson and Catherine Aulia all lost.

Australian Associated Press