The most anticipated match of the 2020 Australian Open will play out on Rod Laver Arena on Monday as bitter rivals Nick Kyrgios and Rafael Nadal meet in the fourth round.

On play alone there's enough to captivate.

The Spanish 19-time grand slam winner and all-time great up against the most gifted shot-maker of his generation playing in front of his home crowd.

Nadal leads 4-3 in career meetings; Kyrgios 2-1 on hardcourts.

The backstory only adds more spice to the rivalry.

In a podcast last year, Kyrgios labelled Nadal "super salty" and accused the Spaniard of not giving enough credit to players who beat him.

It appeared to fire up the 33-year-old for last year's Wimbledon clash, a gripping match which Nadal won in four sets.

Kyrgios admitted after the second-round clash that he had aimed to hit Nadal "square in the chest" when the Spaniard was at the net.

"Why would I apologise? Dude's got how many slams? How much money in the bank account? I think he can take a ball to the chest," Kyrgios said.

After his epic win over Karen Khachanov, Kyrgios wasn't talking up their apparent enmity - but he wasn't talking it down either.

"If we don't like each other or whatever, I think there's a layer of respect. He's one of the greatest of all time. I also read that he thinks I'm good for the sport," Kyrgios said.

"There's a layer of respect that we both have for each other. Doesn't necessarily mean we like each other, but ... we're going to go out there and give contrasting styles and personalities."

Equally, Nadal gave just enough to suggest there could be a detente - or could just as easily get heated again.

"I don't know him personally, honestly, to have a clear opinion," he said after his own third-round win earlier on Saturday.

"It's clear, of course, that when he does stuff that in my opinion is not good, I don't like.

"When he plays good tennis and he shows passion for this game, he is a positive player for our tour."

Monday's winner will play either fifth seed Dominic Thiem or 10th seed Gael Monfils in the quarter-finals.

Australian Associated Press