The Serb’s 6-2, 6-1, 6-2 triumph over 22nd-seeded home hope De Minaur was an ominous statement of intent. Significantly, his troublesome left hamstring appeared much improved.

Asked afterwards how he had been so emphatic, Djokovic told the crowd, “Because I wanted to.

“I cannot say I’m sorry you did not watch a longer match. I really wanted to win in straight sets.”

The 35-year-old called it his “best match of this year so far” and of his hamstring said, “I did not feel anything today, so today was great.”

Rublev admitted he was “lucky” after saving two match points against Rune, in energy-sapping heat.

He described beating the 19-year-old as “not like a rollercoaster, it’s like they put a gun to your head. A rollercoaster is easier.”

In a men’s draw decimated by shocks, including the second-round exit of reigning champion Rafael Nadal, there will be a last-eight clash between two unseeded Americans.

The 20-year-old Ben Shelton, on his first trip outside the United States, emerged from another five-setter against friend and fellow American JJ Wolf.

Shelton is only the fourth man in the past 20 years to reach the Melbourne quarter-finals on debut.

“I really focused in the fifth set, just being energetic, trusting my fitness and just hustling, being courageous and I thought I did a really good job of competing at the highest level in the fifth set,” said the 89th-ranked Shelton.

He plays Tommy Paul, who defeated 24th seed Roberto Bautista Agut.

‘Not comfortable’ Garcia

In the women’s draw, Garcia became the latest top-10 seed to fall, with a shock defeat to Magda Linette, ranked 45 in the world.

This is the first Grand Slam since the Open era began in 1968 to lose the top two seeds in both the men’s and women’s draws before the last eight.

Unseeded Pole Linette stunned Garcia 7-6 (7/3), 6-4 and the French player admitted that expectations and nerves got the better of her.

Asked if being one of the favourites for the title had been too much to handle, she replied: “Yes, I think so.

“It’s one of the things I’m not comfortable with.”

Linette said she “couldn’t believe it” as she reached her first Grand Slam quarter-final at the age of 30.

She faces Karolina Pliskova after the former world number one romped past China’s Zhang Shuai 6-0, 6-4.

Sabalenka never really looked like she would follow top seed Iga Swiatek, Garcia and the rest out of the first major of the year.

The Belarusian Sabalenka and third-seeded American Jessica Pegula – both chasing a maiden major crown – are now the women to beat.

Sabalenka defeated dangerous 12th seed Belinda Bencic 7-5, 6-2 to set up a last-eight clash against unseeded Donna Vekic, who beat 17-year-old Linda Fruhvirtova in three sets.

Hard-hitting Sabalenka sprinted into her first quarter-final at the Australian Open and said, “My whole life, it took me a little while to understand that negative emotion is not gonna help you on court.

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