Shane Warne said Australia had had the better of the first day at The Oval but that they would need to drive home their advantage on day two.
"It's an important day," said Warne, who took 5-118 to leave England 319-7.
"Matthew Hoggard can hang around and (Geraint) Jones can be dangerous so we need to try and knock them over - we can't allow them to wag.
"We're just ahead, I think the last hour has just given us the edge and it was another fascinating day's cricket."
Warne paid tribute to Andrew Strauss following the England opener's century, but added it was not without some fortune.
"I think he would be the first to say he had a bit of luck," Warne observed. "He hung in there and toughed it out, which is one of the hallmarks of the series."
Despite his success, Warne was disappointed to be bowling first after Ricky Ponting lost the toss.
He said: "I much prefer to bowl in the second and fourth innings. To bowl on day one I used all my experience to change the pace and flight of the ball.
"There wasn't much on offer from the pitch so I had to make subtle variations with my deliveries and it worked."
The master spinner sent down 34 overs, 18 of which were bowled in succession in his first spell.
"It shows what a fit athlete can do," he quipped.
He appeared to be suffering with a finger injury but said: "I felt a shock through my fingers like a cramp, but the last few balls were OK."