Pat Rafter is warning Alex de Minaur to batten down the hatches as the nation's great white hope strives to enter uncharted waters at the Australian Open.

De Minaur squares off with American young gun Alex Michelsen on Monday looking to become the first Australian since Lleyton Hewitt 20 years ago to reach four consecutive grand slam quarter-finals.

After dismantling Michelsen 6-1- 6-0 6-2 at last year's French Open to start that glorious grand slam run, de Minaur will enter the rematch a warm favourite to progress to the last eight in Melbourne for a first time.

But in taking out 2023 Open runner-up Stefanos Tsitsipas and 19th-seeded former semi-finalist Karen Khachanov already this campaign, 20-year-old Michelsen has proven he has the firepower to blow de Minaur off the court.

Former world No.1 Rafter, a semi-finalist at Melbourne Park in 2001, is backing de Minaur to advance, while cautioning the eighth seed to be wary.

'I back him against Michelsen,' Rafter said on Sunday.

'I know Michelson's got a really big game. Can he keep it together against someone like Alex? I think it's a bad match-up for Michelsen personally.

'But this guy's got a really big game and, if he can keep it together, he can cause a lot of destruction, I think Michelsen.'

An under-the-weather de Minaur lost to Michelsen in their only other previous meeting, last year in Los Cabos, and is suitably wary of the world No.42.

'He's been playing really well. He's a dangerous opponent with a lot of confidence now. He's taken some big scalps this week, so I'm ready for a battle,' de Minaur said.

'He's going to go out there with no fear. I'm going to do my best to make it difficult for him.'

Michelsen remembers his win over de Minaur fondly, but knows he may need to red-line to repeat the upset over the Open's eighth seed.

'I went out there and didn't miss a ball for an hour and a half or however long that match went. I couldn't miss,' he said.

'I was playing way above my level at the time. It's always nice when that happens. It's pretty rare.

'That's what happened last time, just I couldn't miss a ball.'

A quarter-finalist at Roland Garros, Wimbledon and the US Open last year, de Minaur has fallen in the fourth round in Melbourne on his past three visits.

But the 25-year-old feels he learnt a valuable lesson during his four-set third-round escape on Saturday against Francisco Cerulondo.

'Looking back at this, I reckon this is probably the first match that I've played here in Oz where I didn't feel comfortable,' de Minaur said.

'I felt all of a sudden a little bit of pressure playing. I didn't know what to do.

'I just told myself, 'Yeah, go out there and compete'.

'A part of me knew that at some point there was going to be always a match where pressure was going to be there and the nerves were going to be there, kind of the expectation was going to be there.

'I knew it was going to be a part of it. I just told myself to go out there, compete and, Jeez, I'd rather win ugly any day over losing pretty.

'Ultimately I lived to fight another day. My next one I'll make sure I bring a better level.'

Should de Minaur survive his next test, he will play either defending champion and world No.1 Jannik Sinner or 13th seed Holger Rune on Wednesday for a place in the semi-finals.