AUSTRALIA centre Matt Giteau is unfazed at the prospect of trying to stop Wales’ juggernaut midfield in their tracks at Twickenham, writes Chris Kirwan.

The Toulon playmaker, 84kg, is comfortably the smallest member of the midfields with his partner Tevita Kuridrani weighing in at 104kg while Warren Gatland has paired Jamie Roberts with George North, 110 and 107kg respectively.

Wales will attempt to be direct but speedster North also has the ability to go on the outside break, giving the Wallabies plenty of food for thought in defence.

"They use Roberts as their go forward, traditionally that's just what they've done," said Giteau.

"But they've brought North into the centres as well to get a little bit more ball.

“He probably hasn't seen as much as he would've liked in their first few games. He's obviously a dangerous runner.

"They did the same against Australia last year, I was commentating that game. They obviously see it as an effective weapon against Australia."

Australia have a pretty imposing attacking weapon of their own in the form of full-back Israel Folau, who has overcome an ankle problem and will slot in at 15 despite sitting out the final run-through.

“It’s not 100 per cent but I’m confident, otherwise I wouldn’t be strapping on the boots and going out there,” he said.

“I’m sure every player throughout the tournament gets little niggly injuries that you have to overcome as best you can.

“My body comes first. If I wasn’t right I wouldn’t play. It wouldn’t be fair on the team at all, going out there and playing half-hearted. I feel like I can do the job."

Wallabies head coach Michael Cheika, meanwhile, is braced for a punishing encounter with Wales after both teams booked last-eight places from the tournament's so-called pool of death, with England left trailing in their wake.

Cheika said: "We are still right in the middle of what is pretty much a war zone, our group.

"The goal has been to keep trying to win to get out of our pool, and then go on and keep doing it from there.

“It will, I feel, be the most brutal game we are going to encounter in the pool.

"It has been physical so far, but my knowledge of tournament play tells me that the further on it goes, the more brutal it gets because the stakes get higher and everyone wants to win more."