Williams aiming for game of his life against Wallabies

Shane Williams is gearing up for the performance of his life in Wales' crucial Pool B game against Australia in Cardiff on Saturday.

The elusive Ospreys winger made his mark at the last World Cup with an electric display against New Zealand in Wales' final pool match – but that was in a losing cause. Four years on, Williams feels at the peak of his powers and is determined to inspire a rousing Welsh performance in front of a sold-out Millennium Stadium crowd.

A victory for Wales would almost certainly see them finish top of Pool B and book a quarter-final meeting with the losers, rather than the winners, of the England-South Africa match. This would boost their chances of meeting struggling England, rather than the dangerous South Africans. It is the pivotal match of the pool and, after a disappointing display against Canada last weekend, Williams knows it is now or never for himself and for Wales.

"I want a big World Cup," he said. "I feel a much better player now than four years ago and I want to be able to show that on the field. I feel sharp on the field and I am really excited about playing rugby. I expect big things of myself and I feel really good at the moment. My results in tests have gone through the roof.

"I have hit 30 now and I seem to be getting quicker. I am like a fine wine, I suppose! This World Cup has come at the right time. I do set myself big targets. I really do want a big World Cup for myself."

Australia have made two changes for the Wales game and bolstered their forward power on the bench.

Drew Mitchell, who scored two tries as a replacement in the Wallabies' opening 91-3 win over Japan, will start on the left wing ahead of the injured Adam Ashley-Cooper.

In the pack, Al Baxter has made way for Guy Shepherdson at tight-head prop – but speculation that head coach John Connolly would start with both Phil Waugh and George Smith in the back row proved unfounded. Instead, Waugh is one of five forwards on the Australia bench.

Ashley-Cooper injured his toe in Sunday's victory in Lyons and has been given until tomorrow to prove his fitness, otherwise Julian Huxley will be on the bench.