MELBOURNE - Novak Djokovic brushed aside fitness concerns with a vintage performance to thrash Alex de Minaur in the fourth round, but women's fourth seed Caroline Garcia on Monday became the latest high-profile casualty at the Australian Open.

Nine-time champion Djokovic has battled a hamstring injury throughout the tournament, but moved freely to overwhelm the Australian 22nd seed 6-2, 6-1, 6-2 and silence the home fans at Rod Laver Arena.

In their first match-up, the fleet-footed de Minaur hoped to exploit Djokovic's ailment but he was blown off the court by the spectacular Serb, who rediscovered his best form in his march towards a record-equalling 22nd Grand Slam title.

"I really wanted to win in straight sets. I kept my focus all the way through and it was my best result of the year," Djokovic said.

"I didn't feel any (hamstring injury) today. I know things can change quickly, so I don't take anything for granted."

Djokovic booked a blockbuster quarterfinal with fifth seed Andrey Rublev, who survived a fierce examination from rising Danish star Holger Rune to prevail 6-3, 3-6, 6-3, 4-6, 7-6 (9).

The Russian survived two match points in the 12th game of the fifth set and then found himself on the brink of defeat trailing 0-5 in the match deciding tiebreak.

But he dug himself out of a hole to storm into the quarterfinals for the seventh time in his Grand Slam career, but he has never progressed further.

"I think I was never able to win matches like this and this was the first time ever that I won something like this to be in the quarterfinal," said Rublev, who was down 5-2 in the fifth set before storming back.

American Ben Shelton continued his dream Australian Open debut after overcoming compatriot J.J. Wolf with a tense 6-7 (5), 6-2, 6-7 (4), 7-6 (4), 6-2 victory.

The 20-year-old will play Tommy Paul in an all-American quarterfinal in what has been a resurgence for men's players from the US.

Paul defeated Spain's 24th seed Roberto Bautista Agut 6-2, 4-6, 6-2, 7-5.

The upsets at an unpredictable tournament continued when Garcia of France fell to 45th ranked Magda Linette 7-6 (3), 6-4 in the women's singles.

It was a bitter disappointment for Garcia, who has had a career revival in the last 12 months and eyed a first Grand Slam triumph.

But she'll have to wait after 30-year-old Linette reached her maiden Grand Slam quarter-final.

Linette of Poland will face former world number one Karolina Pliskova, who ended a strong run from China's Zhang Shuai 6-0, 6-4.

Zhang, the last remaining Chinese player in either the men's or women's singles draw, fell to Pliskova for the eighth straight match.

The 23rd seed Zhang was unable to match her fairytale quarterfinal runs at the 2016 Australian Open and 2019 Wimbledon.

But she did reach the last 16 for the second straight Grand Slam after making the fourth round at last year's US Open.

In-form Aryna Sabalenka has ascended to title favouritism alongside third seed Jessica Pegula after comfortably defeating Belinda Bencic 7-5, 6-2.

The fifth seed set up a last-eight clash against unseeded Donna Vekic, who overcame a mid-match stutter to beat 17-year-old Linda Fruhvirtova 6-2, 1-6, 6-3.

Notably playing with a steelier edge, Sabalenka has been in irresistable form as she strives for a maiden Grand Slam trophy.

"My whole life, it took me a little while to understand that negative emotion is not gonna help you on court," she said.

"You have to just stay strong and believe no matter what and then do everything you can."

Title favourite Pegula and men's third seed Stefanos Tsitsipas highlight quarterfinal action on Tuesday.