Michael Cheika praised his Australia side for showing "a different skin" in their 15-6 Rugby World Cup win over Wales but feels the Wallabies still have plenty of improvements to make in order to reach the final.
Australia survived a second-half spell in which they had just 13 men on the field after Will Genia and Dean Mumm had been sent to the sin bin in the space of three minutes to hold on and claim victory in Saturday's clash at Twickenham.
The triumph sees the Wallabies finish top of Pool A and set up a quarter-final meeting with Scotland a week on Sunday, while Wales now take on South Africa in the last eight.
Cheika said: "It was pretty tight. It was a different type of game for us so we just had to show a different skin.
"There were plenty of imperfections and that's something we have to sort if we want to get to the final."
Asked for his thoughts on Scotland, Cheika added: "We haven't had a good look, to be honest. What I do know is that Vern Cotter is a very clever coach.
"He had a very successful time in France, which is difficult for an Anglo-Saxon and I'm sure he will have them ready for the knockout games.
"There is no favourable side of the draw. The only favourable thing is that you are in it. You have only got to look at some of the games in this tournament to know there are no easy games."