Whether it's a hangover from the Novak Djokovic saga or the swirling threat of Omicron, fans have shunned day one of the Australian Open at Melbourne Park.

After 10 days dominated by Djokovic's visa fiasco, which led to the defending champion and top seed being deported from Australia before a ball toss, the Open looked to have lost its usual lustre.

The Victorian government announced last week crowd capacity would be capped at 50 per cent during the next fortnight in line with the state's COVID-19 protocols.

In another deterrent, those who did venture out to Melbourne Park were greeted by long lines for a vaccination certificate check with only the double vaxxed permitted through the gates.

With grey skies overhead early on and blustery winds following in the afternoon, the normally bustling garden square resembled a ghost town leaving entertainers to perform to just a few.

While lucky loser Italian Salvatore Caruso took Djokovic's spot at the top of the men's draw, the world No.1 still proved a favourite with some fans taking photographs at the main stadium in front of an image of Djokovic holding up the trophy he won each of the past three years.

Djokovic's ban may have accelerated the inevitable, with fixtures from the past two decades like Swiss maestro Roger Federer and the Williams sisters, Serena and Venus, all missing.

Organisers will be hopeful that spectators warm to the occasion, with Australia's world No.1 Ash Barty a hot favourite to lift the women's crown.

Those that did front got behind Aleksandar Vukic, who claimed his first win at a grand slam with a stirring four-set upset victory over South Africa's 30th seed Lloyd Harris.

"This is totally a dream," Vukic said after receiving a rousing standing ovation from the Court 3 crowd.

"Especially this court, with all these guys. I mean, I came here as a kid and I was watching the Aussies play here. To play here, myself, and to get the win ... I can't put it into words."

Vukic said he was nervous closing out the match but overjoyed to take the win in front of his emotional parents and family.

"These guys were with me every point," he said.

"I knew I wasn't alone. I couldn't have done it without them. This is a dream."

Barty was scheduled to take on Ukraine's Lesia Tsurenko and is a hot favourite to break Australia's infamous 44-year Open title drought.