Australia seamer Stuart Clark insisted they were taking nothing for granted despite a dominant day two performance in the third Test in Perth.
Australia can render the final two Tests meaningless with victory here
Clark took 3-49 as England were bowled out for 215 and Australia, already 2-0 up in the series, led by 148 at stumps.
"We will be focused on Saturday.If we don't bat well there is every opportunity England can win," he said.
"It's an indifferent sort of wicket, a lot of guys are not sure what is going to happen next."
Clark, who took nine wickets in his debut Test against South Africa at Cape Town in March, admitted that he was still amazed to be an integral part of an Ashes series.
"I still wake up and think it's not real, but I'm enjoying every minute," said the 31-year-old, who now has 14 wickets in the series and has only once failed to strike in his 13 Test innings with the ball - ironically against minnows Bangladesh.
He was fortunate to claim the wicket of Andrew Strauss in the 11th over of the second morning to a hugely debatable caught behind decision, but there was no doubt about Sajid Mahmood's edge to the keeper.
Clark then returned to end a promisingly defiant final wicket stand of 40 between Steve Harmison and Monty Panesar.
"Length is important on this wicket, especially early on when the ball is hard," he said. "When the ball softens us batting wasn't as difficult.
"You need to get the ball up and get the batsmen driving, it's a new ball wicket."
The seamer added that Australia had been content to frustrate the only England batsmen that were able to settle, Andrew Strauss and Kevin Pietersen.
"That's the format with a lot of Test cricket these days," he said. "There are a lot of flat wickets around so you try and restrict the scoring and let them make the mistakes."