With the world No.1 ranking on the line in Perth, Australia have been warned to beware of Dale Steyn.
The world's premier fast bowler has been well down on form so far this series and South Africa have regularly opted not to unleash their main weapon when you'd be expecting him to be thrown the ball.
Proteas captain Graeme Smith has failed to inject Steyn into the attack at the right times, particularly with new batsmen in or after breaks in play.
Steyn has just five wickets to show from two Tests.
However Australian coach Mickey Arthur says his team cannot afford to get complacent against one of the fiercest competitors in world cricket.
Arthur spent years coaching Steyn and says he learned that the 29-year-old saves himself for the big moments.
And it doesn't get much bigger than a series-deciding showdown at the WACA to determine who is the world's best Test team.
"Dale stands up in games that are on the line," Arthur said.
"I think we saw a little hint of that through this Test match (second Test in Adelaide).
"I'm expecting Dale to really bound in at Perth.
"We know Dale is world class, we've put a lot of preparation into how we wanted to play him and I think we've played him nicely ... but Dale is a quality class act."