Australia coach Michael Cheika has taken the blame for his side's error-strewn display against Scotland in the Rugby World Cup quarter-finals.

The Wallabies required a controversial late penalty from Bernard Foley to beat Vern Cotter's men 35-34 at Twickenham on Sunday and secure a last-four meeting with Argentina.

Fly-half Foley and replacement prop James Slipper were each culpable for Scotland tries in the second half as Australia - so impressive throughout the pool stage - came perilously close to exiting the competition.

Reflecting on a below-par display, Cheika said: "I've got to take a lot of responsibility for the team not filling its potential on Sunday.

"I think I let the team think too much about the games before. They were still thinking about the game against England and the game against Wales and I let that atmosphere stay.

"I should have just wiped those things out and just focused on the next challenge and just focused on the Scottish scrum or whatever it was.

"I don't feel that I, as the coach, performed very well last week in preparing the team for that quarter-final.

"I'll make sure that doesn't happen again this week."

Australia's bid for World Cup glory has been enhanced by the contribution of scrum coach Mario Ledesma, a distinguished former Argentina international who will now aim to mastermind victory over his home nation.

Cheika added: "It's obviously a big week for him, very emotional, but he'll stay focused on getting our scrum to improve and it needs to improve because there is obviously a very strong [Argentine] scrum."