Djokovic beat Jo-Wilfried Tsonga in straight sets but was not at his brilliant best as he set up a clash with Denis Shapovalov.

Milos Raonic and Kei Nishikori progressed with victories over Stan Wawrinka and Ivo Karlovic, while Dominic Thiem retired after feeling unwell in his clash with Alexei Popyrin.

Alex Bolt pulled off an upset against Gilles Simon, and the young guns continued to impress, with Borna Coric among the other winners in Melbourne.

World number one Djokovic had to work hard for his 6-3 7-5 6-4 victory over Tsonga on Thursday.

In an entertaining encounter, Tsonga showed glimpses of the talent that once saw him ranked fifth in the world but mixed box-office shots with silly errors as the more consistent Djokovic plugged away despite not being at the top of his game.

The six-time champion punished Tsonga's mistakes to take a convincing scoreline from a match against an opponent who appeared capable of more.