Looking to end a 49-year drought since Australia celebrated a local men's winner, de Minaur lodged a convincing 6-0 7-6 (7-5) 6-3 victory over rising American Alex Michelsen on Monday night.
The victory sets up a blockbuster clash on Wednesday night with world No.1 Jannik Sinner.
"It means the world. There's nothing I want to do more than play well in Australia," the 25-year-old said.
"I'm super happy to finally break through, finally get that milestone moment here at the Australian Open.
"It felt like the slam that kept on slipping away where I felt like I had a little bit of a barrier at the fourth round, so it feels very good to finally break through another milestone in my career.
"I've worked really hard on myself to give myself these opportunities and chances, and it hasn't been overnight, it's been a long process, but I'm glad that I'm showing this consistency, and it's a good feeling to have four back-to-back quarter-finals at slams."
As well as the chance to make his first semi-final at Melbourne Park in his ninth appearance, the win ticked off a number of career landmarks.
De Minaur is the first local into the last eight since Nick Kyrgios in 2015 and the first Australian to make four consecutive grand slam quarter-finals since Lleyton Hewitt surged all the way to the 2005 Australian Open title match.
But a giant challenge looms in the form of defending champion Sinner, who de Minaur hasn't beaten in nine attempts and not even taken a set off since 2020.
An unwell Sinner overcame Denmark's Holger Rune in four sets in his fourth round clash earlier in the day.
"I'm looking forward to it, obviously," said Australia's world No.8.
"It's going to be an incredibly tough match and I'm going to have to do something I haven't done before. But why not start here?"
A nervous Alex Michelsen took time to settle into the match, losing the first set 6-0. (James Ross/AAP PHOTOS)
In the first set at Rod Laver Arena on Monday night, the eighth seed certainly looked like he could give the rangy Italian a shake.
De Minaur played liked a man on a mission, completely outclassing the 20-year-old Californian, who had never previously progressed past the second round of a major.
Michelsen tallied 17 unforced errors, his performance in stark contrast to the player who claimed the scalps of world No.11 and 2023 Open runner-up Stefanos Tsitsipas and 19th seed Karen Khachanov in the early rounds.
But with de Minaur's first serve faltering, world No.42 Michelsen worked his way into the match in the second set.
The Australian blew a break point to go ahead 3-0 and then multiple chances for a 4-1 lead with his big-hitting rival taking advantage.
Michelsen led 6-5 before de Minaur took the set into a tie-break, with a crucial ace at 5-5 helping him secure a two-set lead.
The Wizard of Aus.— #AusOpen (@AustralianOpen) #AO2025 • @alexdeminaur pic.twitter.com/edLkgs557cJanuary 20, 2025
In the third set the Australian No.1 broke his rival to go ahead 4-2 and while there were a few nervous moments as he served for the match, he was able to close it out.
"I had my opportunities in the second set to maybe run away with that one as well and not let him inside of the match but I wasn't able to close out," de Minaur said.
"He obviously raised his level and made it a tough match ... the second set was pivotal."
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