Nick Kyrgios entertained but left empty-handed again as Rafael Nadal won a compelling fourth-round contest at the Australian Open.

Kyrgios, a huge basketball fan, was close to tears as he walked onto Rod Laver Arena wearing Kobe Bryant's LA Lakers vest in tribute to the star, who died on Sunday.

And initially it appeared the emotion of the occasion, coupled with physical fatigue after his four-and-a-half-hour battle against Karen Khachanov two days before, would prevent him making a fight of it.

But Kyrgios, driven by his efforts in raising money for victims of the wild fires, has been keen to show Australia that he cares on court as well as off it.

He roused himself at the start of the second set and, had he taken an extraordinary third set, the outcome might have been different but, as with their clash at Wimbledon last summer, it was Nadal who prevailed 6-3 3-6 7-6 (6) 7-6 (4).

That contest had a real edge to it after some very public needle, with Nadal accusing Kyrgios of lacking respect following a feisty match in Acapulco and the Australian branding his opponent "super salty" in an interview on the No Challenges Remaining podcast.

Nadal leapt in the air when Kyrgios' final forehand landed in the net, and it is he who moves through to a quarter-final against Dominic Thiem tomorrow.