De Minaur stood two points away from a precarious two-set deficit before fighting back to clinch a spirited 5-7 7-6 (7-3) 6-3 6-3 win over a gallant but fatiguing Francisco Cerundolo on Saturday.
De Minaur has never won a grand slam match from two sets to love down and had to pull out all stops to avoid needing to in a tense three-hour, 53-minute scrap on Rod Laver Arena.
Alex De Minaur was stretched to get past Francisco Cerundolo and into the fourth round. (Joel Carrett/AAP PHOTOS)
The great escape vaulted the home hope into the last 16 for a fourth consecutive year and extended de Minaur's quest to become the first Australian man to win the Open since Mark Edmondson in 1976.
The 25-year-old also joins legends Rod Laver, Roy Emerson, John Newcombe, Tony Roche and his Davis Cup captain and mentor Lleyton Hewitt as only the sixth Australian man in the Open era to make the fourth round at six consecutive majors.
But the narrative could have been very different - and de Minaur acknowledged as much after scraping through to the second week.
"It was definitely not pretty. I found a way," said the world No.8.
"That's all I need to do in these moments - find a way to get through the first week.
"I'm glad I found a way to get over the line. Even if I don't play my best, I'm going to compete till the end."
De Minaur wasn't only competing, but thriving as 31st-seeded Cerundolo faded in a sapping centre-court encounter.
"The legs are back," de Minaur declared triumphantly of the message he was sending when repeatedly slapping his thighs after miraculously chasing down a drop shot to gain a decisive late service break.
"It was a big point. It got the crowd on my side.
"I'm going to have a couple of bruises on my quads but it was worth it."
Off his game and down a set, de Minaur again gave up an early break in the second set before using a short timeout to regroup while a spectator was escorted from RLA after a medical episode.
The eighth seed sought advice from his courtside box, including Hewitt, and immediately lifted, almost breaking from 40-0 down on Cerundolo's serve.
De Minaur was again in trouble after being unable to break back and was staring down the barrel of a two-set deficit serving at 5-6, 15-30.
Francisco Cerundolo fist pumps after claiming a point. (Joel Carrett/AAP PHOTOS)
But he rallied to take the set in a tiebreaker and urged the crowd to will him to victory.
He sure needed them to.
Despite Cerundolo needing treatment for a quad strain early in the third set, de Minaur couldn't shake the Argentine.
But he finally prevailed when Cerundolo double-faulted on match point to send de Minaur through to a fourth-round meeting with unseeded American Alex Michelsen on Monday.
Michelsen earlier ousted 19th seed Karen Khachanov in straight sets to become the youngest American since Pete Sampras and Andre Agassi - who won six Australian Open crowns between them - to snare two top-20 scalps at a grand slam in 35 years.
"Look, he's been playing some amazing tennis this week," de Minaur said.
"Took out Stefanos (Tsitsipas). Today, Khachanov.
"He's a kid playing with a lot of confidence, so I'm expecting, again, another battle.
"But I love these battles. I can't wait."
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