Wallabies captain Stephen Moore will this week play his 100th Test -- not that you would know it from talking to him.

The veteran Wallabies hooker and returned centre Matt Giteau will both notch 100 caps when they run out onto Twickenham on Sunday in Australia's Rugby World Cup quarterfinal against Scotland.

But Moore is doing his absolute best to play down the achievement and it's with good reason when you consider two of his last three Tests against the Scots have finished in defeat.

"I probably had a bit more hair back then, that was the main difference," Moore said when asked to recall his Test debut.

"It's not really a week to be reflecting on things. We've got a great opportunity to play in a quarterfinal at a World Cup and that's more than enough to play for.

"So I don't want the boys thinking about anything other than the opportunity we've got, preparing really well this week and playing our best rugby on the weekend because we're going to need to do that against Scotland."

Australia haven't faced Scotland since 2013 when they triumphed 21-15 in a tight encounter at Murrayfield. The Scots were victorious in the two Tests that preceded that clash though, with the one-off Test in Newcastle, Australia, proving a particularly dark night for the Wallabies.

"Pretty average, I opened the curtains during the day and I saw one of the bins rolling down the street," Moore said when asked about the cyclonic conditions in Newcastle in 2012.

"I thought, 'Oh yeah, this is going to be good'. So [we] got out there and it was one of the toughest conditions I've played in in my whole career.

"It was just one of those nights that the wind was howling and it was raining sideways and they really played well in those conditions. There obviously wasn't many points scored in the game, it was pretty tight, but they controlled the game really well that night. So we know they're a quality team."

The Wallabies enter their quarterfinal as heavy favourites following arguably their best performances of the Michael Cheika era -- a polished display attacking display against England and the almighty defensive effort against Wales.

The Scots, meanwhile, only narrowly avoided a second consecutive pool-stage exit after a thrilling 36-33 victory over Samoa, Vern Cotter's side surviving a late fightback from the Islanders after they had trailed earlier in the match.

Still, Giteau said the Scots had been "really impressive" throughout the tournament -- their skipper, Greg Laidlaw, in particular.

"Their set-piece game looks very strong; obviously they've got a great goal-kicker and captain who leads them around really well," he said.

"They look like a confident team who know what they want and know the style of rugby that they want to play, and they've certainly been executing it quite well."