A Powerplay taken at the 23rd over, yielding only 23 runs from five overs despite the fielding restrictions, was critical in Australia's World Cup Group A 83-run victory over South Africa on Saturday.

Australia failed to defend totals of 336 for four and 346 for five against New Zealand last month and lost their number one ranking to South Africa during the 3-0 series loss to the Kiwis.

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On Saturday, a total of 377 for six had looked more than adequate, despite the short boundaries on the tiny Warner Park ground, after Graeme Smith had won the toss and asked Australia to bat.

Yet when South Africa reached 160 without loss, with AB de Villiers in marvellous touch, the South African supporters started to chant "four-three-eight", a reference to the 438 for nine South Africa scored last year to overhaul Australia's 434 for four in the highest run chase in history.

LOST MOMENTUM

A superb run out after a chase and throw from the boundary which hit the only stump on view from Shane Watson accounted for De Villiers after the South African opener had plundered 92 from 70 balls. 

Ricky Ponting then called for the second compulsory Powerplay, with only two fielders outside the circle, and recalled strike bowler Shaun Tait in combination with Watson's medium-pace.

By the end of the five overs, South Africa had lost momentum and Ponting brought back his wrist spinner Brad Hogg, who had at that stage had bowled four overs for 27 runs.

Hogg finished with three for 61 from 10 and Tait, who bowled four spells, took two for 61, reverse swinging the ball sharply.

"I thought Hogg and Tait through the middle were very good for us and got us key breakthroughs," said Ponting as he reflected with satisfaction on a good day's work.

"I think for the whole team to get through this sort of challenge will be great for us. The last few times we have been challenged that way we haven't performed at our best.

"I think today we just have to keep hanging in there and wait for something special in the field which is what happened today."

Tait's speed and Hogg's spin are crucial to Australia's plans and both fully vindicated their captain's support. Nathan Bracken, too, played a full part with two for 40 from nine overs of left-arm medium-paced cutters.

"Taking those points through with us and taking a pretty healthy run rate through with us as well is an ideal start to the tournament," Ponting said.

"That's one of the games down and we have to focus and turn things around pretty quickly and focus on a big game against the West Indies on Tuesday."