Rafael Nadal progressed to the Australian Open quarter-finals with a straight-set win over Adrian Mannarino as the Spaniard continues his quest for a record-breaking 21st major title.

Mannarino struggled with injury after the tie-break, as the sixth seed went on to claim a 7-6 (16-14) 6-2 6-2 win.

Nadal plays Denis Shapovalov next after he beat third seed Alexander Zverev.

Canadian 14th seed Shapovalov, 22, reached his first Australian Open quarter-final with an impressive 6-3 7-6 (7-5) 6-3 victory against Germany's Olympic champion.

The exit of the 24-year-old Zverev, a 2020 semi-finalist, leaves Nadal as the highest ranked player remaining in the top half of the men's singles draw.

It proved a frustrating match for Zverev, one of the pre-tournament favourites after winning the ATP Finals for a second time in November, and his wait for a first Grand Slam title goes on.

Nadal, the 2009 champion and five-time finalist in Melbourne, also faced four set points in a remarkable opening set which lasted one hour and 22 minutes on Rod Laver Arena.

Mannarino had come through a mammoth four-set match against Russia's 18th seed Aslan Karatsev that lasted four hours and 48 minutes in the previous round.

And the breathless battle at the start of this match took its toll on the 33-year-old Mannarino, who had a problem with his knee and groin and was subsequently broken in the opening game of the second set.

Nadal made a fast start in the third too, breaking Mannarino in the opening game once again, but despite struggling the Frenchman rallied and broke back to love.

He could not deny Nadal in third game, despite saving five break points - the Spaniard taking his sixth chance to begin a four-game run to move clear and seal victory in two hours and 43 minutes.

"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 added: "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."

The only former Melbourne champion remaining, Nadal faces a tough challenge against Shapovalov in the last eight as he looks to seize his opportunity in the absence of fellow 20-time Grand Slam winners Novak Djokovic and Roger Federer.

"It's always an honour to go up against a guy like Rafa," Shapovalov said.

"It's always going to be a battle against him. It's going to be a tough one but I'm going to enjoy it."