An imperious Aryna Sabalenka stayed on course for a historic third consecutive Australian Open crown on Sunday, while Novak Djokovic and Carlos Alcaraz can later set up a blockbuster quarter-final.

Double-defending champion Sabalenka blew away Russian 17-year-old Mirra Andreeva 6-1, 6-2 in a ruthless display on the hottest day of the Melbourne tournament so far.

Djokovic continues his quest for a record 25th Grand Slam title against Czech 24th seed Jiri Lehecka in the prime-time evening match on Rod Laver Arena.

The prize for the winner is a meeting with either Carlos Alcaraz or Britain's Jack Draper for a place in the semi-finals.

Belarus's Sabalenka was out in the 32 Celsius (89.6 Fahrenheit) centre court heat for only 62 minutes before registering an 18th consecutive win at Melbourne Park.

"I'm super happy to get through this difficult match in straight sets," said Sabalenka, who will face either Croatian 18th seed Donna Vekic or 27th seed Anastasia Pavlyuchenkova from Russia in the last eight.

She struggled with her serve in colder conditions during the first week, but was untouchable as the mercury soared at the start of the second.

"The ball was flying like a rocket. I hope conditions are going to be the same till the end of the tournament," said Sabalenka.

In the other last-16 women's singles matches Sunday, in-form American third seed Coco Gauff plays Switzerland's Belinda Bencic.

The winner will meet either Spanish 11th seed Paula Badosa or Olga Danilovic of Serbia.

In the men's draw, American 12th seed Tommy Paul plays Spain's Alejandro Davidovich Fokina as he bids to match or better his semi-final appearance from 2023.

- 'Best I've played' -

Whoever comes through that clash will meet either German second seed Alexander Zverev, who is yet to drop a set, or French 14th seed Ugo Humbert. They face each other on John Cain Arena.

The 37-year-old Serbian Djokovic appears to be growing into the tournament, an ominous sign for his rivals.

He dropped a set in each of his opening two matches but swept past Tomas Machac 6-1, 6-4, 6-4 in the third round.

"There's always something to improve, work on, but this is definitely the best match I've played in the tournament," said Djokovic, who has won the Australian Open 10 times and has Andy Murray as coach this time.

Marathon man Draper promised to make Alcaraz battle after the Briton came through all three of his previous matches in five sets, and all from 2-1 down, to set up a clash with the four-time Grand Slam winner.

"I need to be brave in the way I play," said Draper, the 15th seed.

Gauff, on a 12-match win streak and yet to drop a set this season, said she just wanted to enjoy the ride after beating Leylah Fernandez in the third round.

The 20-year-old is the highest-paid woman athlete in the world, according to Forbes magazine.

Despite her wealth and fame she said she was determined to stay humble.

"I grew up in the church. I think when you just grow up in the community like that you have no choice but to keep your grounding," Gauff said.

"I'm so lucky to be able to do what I do, also get paid while doing it. I'm very grateful."

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