Preview: S.A v Australia

The world champions, who meet South Africa in Wednesday's second semi-final, are only two games away from an unprecedented World Cup title hat-trick. They have not been defeated in the tournament since losing to Pakistan in the 1999 group stages.

"This time around we have played a brand of cricket right from the first ball of almost every game that hasn't allowed our opposition into the game," Ponting told a news conference.

"We probably haven't been challenged as far as the closeness of the games go but we challenged ourselves right the way through to keep playing excellent cricket and improve on each game.

"We've got 100 overs tomorrow to see if we can keep challenging ourselves and see if we can make some more improvements."

One-day cricket, where early pitch conditions and the toss of the coin can play a disproportionate role, encourages the underdogs.

Ponting's genius has been to minimise the role of luck in different conditions throughout the Caribbean and help create a team which can overcome any obstacles.

Coach John Buchanan said the Australians always looked to play the perfect game.

"You'd like to play the perfect game," he said. "To play the perfect game means you need everything in place before you start and then deliver it through the course of the game. It doesn't mean I'm not concerned going into tomorrow's game."

South Africa briefly disconcerted Australia in the group stages in St Kitts when they reached 160 for no wicket chasing 378 to win. They eventually lost by 83 runs.

"We have discussed St Kitts at length, looked at how Australia played. We have picked up some trends Ponting used during that game," South Africa coach Mickey Arthur said.

"We really spent a lot of time doing our homework.

"This is huge. From our last six encounters, we are three-all. That is the way we are approaching this game."

Arthur said captain Graeme Smith, who has an injured left knee, would be fit and added his team were aiming to emulate the mental approach they adopted in their Super Eights win over England last Tuesday which guaranteed them a semi-final place.

"The guys all know what to do. We have trained hard, they are fit, mentally and technically where they need to be. It is a matter of just keeping them focused, keep their feet on the ground.

"The key word for us has been calmness and not being over-anxious. I don't want the guys to be waking up in the middle of the night thinking 'Cup semi-final'.

"It is a huge game but we are trying to downplay it slightly."

Arthur said left-arm spinner Robin Peterson would be included in the South Africa 12 for a pitch which is expected to be slow. Australia are unchanged.

"It's a good pitch, expect runs to be scored," head groundsman Kent Crafter told Reuters. "It will last 100 overs comfortably."

Australia - Adam Gilchrist, Matthew Hayden, Ricky Ponting (captain), Michael Clarke, Andrew Symonds, Michael Hussey, Shane Watson, Brad Hogg, Nathan Bracken, Shaun Tait, Glenn McGrath.

South Africa (from) - Graeme Smith, AB de Villiers, Jacques Kallis, Herschelle Gibbs, Ashwell Prince, Justin Kemp, Mark Boucher, Shaun Pollock, Andrew Hall, Andre Nel, Charl Langeveldt, Robin Peterson.