Pakistan had torn through Sri Lanka's batting line-up in their Super Eights clash on Monday to set up a 33-run win.
"We have a good chance against Australia, the way we are playing. We must just keep doing what we are doing," Butt told reporters.
"It's very important to take wickets at regular intervals, that's the only way to put pressure on a team. Then the same total we scored tonight [189 for six] will be good against any team, even though Australia are one of the better sides in world cricket and we will have to play well to beat them.
"It's important to divide your best bowlers through the 20 overs and keep one for later. That helps because it is a constant worry for the opposing team that there is still one bowler to come on."
Pakistan exited the 50-over World Cup in the Caribbean in the first round earlier this year, but Butt said there was a totally different atmosphere in the squad in South Africa.
"We are gelling well together and we have forgotten about the World Cup. That has been discussed more than the tsunami.
"It is most important that everyone in the team backs up each other and the team is winning," Butt said.
