Australian coach Michael Cheika revealed that his charges will not fall into the trap of complacency when they run out against Scotland as favourites.
The Wallabies impressed in the 'Pool of Death', winning all their games to earn a spot in the quarter-finals against Pool B runners-up Scotland.
However, Cheika revealed that this will be their most difficult game of the competition so far.
"It's pretty easy because we don’t think we are complacent," said Cheika.
"Nobody was saying that about us however many months ago it was and things aren't any different now. We’re acutely aware that this is really important for our own journey as a team.
"I've seen a lot of the Scottish players saying they can win – and they can, they can. It's the reality of sport and what we need to make sure is that our mindset is really clear on what we’re prepared to do to get that victory.
"This will be the most difficult game we play and that's not disrespecting our other opponents at all because every match has been tough but this will be the toughest.
"There's going to be a lot of pain, it's going to be physical and I want the players to enjoy that as well because that's when it's worth it."
Key to Australia's chances is superstar David Pocock, who is recovering from injury. The flanker is superb at the breakdown, an area that will be crucial to winning Sunday's fixture.
However, despite his value to the team, Cheika confirmed that Pocock will not play if he is not fit enough.
"We'll give him a run before we train today to test his fitness," he said.
"He ran yesterday and got into some work which was pretty positive. No chance for resting. This is knockout footy and every day is our biggest day. If he's fit, he'll play…if he's not fit to do his job, he won't play."