MELBOURNE: Rafael Nadal came out on top of an epic 28-minute opening-set tiebreak in sapping heat to power past Adrian Mannarino into the quarter-finals of the Australian Open on Sunday.

The 20-time Grand Slam champion needed all of his experience and resolve to go on and claim a 7-6 (16/14), 6-2, 6-2 victory in 2hr 40min on Rod Laver Arena to reach the last eight. It is the 35-year-old Spanish great's 14th quarter-final in his 17th visit to Melbourne.

The sixth-seeded Nadal will next face 14th seed Denis Shapovalov in the quarters after the Canadian leftie stunned German third seed Alexander Zverev in straight sets.

"I was a little bit lucky at the end of the tiebreaker, I had my chances but then he had a lot of chances too," Nadal said.

"That crazy first set was so important and the service break at the beginning of the second set too.

"He had been playing some fantastic tennis during the whole tournament, winning against amazing players, and today the first set was super difficult.

"His ball was very difficult to control, very flat, very fast and I am very happy that I survived that."

Nadal is chasing a men's record 21st Grand Slam and coming off a curtailed 2021 season caused by a chronic foot injury followed by a bout of Covid-19 in December.

Nadal was effusive in his praise of his next opponent, 22-year-old Shapovalov, who he leads 3-1.

"He is one of the players with the biggest potential on the tour," he said.

"He has a lot of amazing things on his game, and his results say that. When he's playing well, it's very difficult to stop him."

The story of the match was the extraordinary opening-set tiebreak, where Nadal held seven set points and Frenchman Mannarino four.

It proved an epic in the searing heat, before Nadal prevailed 16-14 after winning a furious rally.

The 69th-ranked Mannarino appeared to injure his groin or abdomen in chasing down a drop shot during the tiebreak and needed treatment courtside.

The effort of the draining 81-minute opening set told on Mannarino, who lost his opening service game of the second set and another break followed in the fifth game as the outcome became inevitable with Nadal taking command.

Mannarino was coming off a 4hr 38min struggle to get past 18th seed Aslan Karatsev in the previous round which finished in the early hours of Saturday.

he gamely battled on but Nadal worked his way to victory to remain unbeaten after seven matches this season.