Stefanos Tsitsipas took inspiration from the watching Rod Laver to stay calm in the face of an onslaught Sunday and battle into a third consecutive Australian Open quarterfinal.

The Greek third seed extended his win streak this year to eight matches with a 6-4, 6-4, 3-6, 4-6, 6-3 triumph over Italian 15th seed Jannik Sinner on Rod Laver Arena as the clock ticked over four hours.

Victory set up a clash against surprise package Jiri Lehecka for a place in the semis after the 21-year-old stunned sixth seed Felix Auger-Aliassime 4-6, 6-3, 7-6 (7/2), 7-6 (7/3).

That upset put the Czech into the last eight at a Grand Slam for the first time after being knocked out in the first round at all four majors last year.

"I just stayed really calm, just like Mr Rod Laver used to do in his day," said Tsitsipas as the crowd roared their approval and Australian legend Laver saluted the Greek player from the stands.

"It was a long match, I felt like I spent an entire century on this court playing tennis.

"What a great night. That was superb, 'a ripper' as they say here. I'm really excited to be sharing moments like this on the court, especially in Australia.

"I'm trying to do my best out here, it's not easy. I had an unbelievable opponent on the other side of the court today," added Tsitsipas, the highest remaining men's seed.

Tsitsipas, who lost in the 2022 semifinals to eventual runner-up Daniil Medvedev, is playing for a double prize — not only a maiden major title but also the number one ranking.

That will be his if he lifts the trophy in Melbourne.

Novak Djokovic, who he cannot meet before the final, can also become the world's top-ranked player should he be crowned for a 10th time in Melbourne.

Tsitsipas led Sinner 4-1 in their head-to-heads leading into the match, including victory in the Melbourne quarterfinals last year, but it proved to be a tough test for the Greek.