Nick Kyrgios pulled out of the Sydney Tennis Classic due to testing positive for coronavirus shortly before he was due to face Italy's Fabio Fognini.

The Australian had been one of the tournament's major draws as the home favourite but now cannot compete and that has subsequently thrown his Australian Open participation into question.

Fognini took full advantage of the situation as he saw off lucky loser Daniel Altmaier 6-3 7-5 to move into the second round.

There he will be joined by – among others – David Goffin, with the Belgian winning a game for the first time in eight months as he beat Facundo Bagnis 6-4 6-4 after an injury-ravaged 2021.

Fifth-seed Lorenzo Sonego was the highest seed in action and he was made to work hard for his 3-6 6-3 7-5 win over Hugo Gaston, needing almost two hours and 45 minutes to get the job done.

The day's other game saw Jordan Thompson win on home soil, beating Marcos Giron fairly comfortably 6-4 6-2.

At the Adelaide International 2, Tommy Paul came out on top in the battle of the Americans as he cruised to an impressive 6-2 6-3 win over Frances Tiafoe in just 69 minutes.

Local boy Aleksandar Vukic clinched the biggest scalp of his professional career as the world number 156 – a wild card entry for the tournament – beat Alexander Bublik 7-6 (7-5) 6-2.

Arthur Rinderknech and Jaume Munar also progressed, the latter defeating Australia's John Millman.