Ponting made top score of 62 in an Australian total of 254 for six. Then he led a fired-up Australian team in the field as South Africa were bowled out for 230, with fast bowler Brett Lee taking four for 48.

South Africa crashed to 69 for five but their hopes were raised when AB de Villiers (68) and Shaun Pollock (69) put on 119 for the sixth wicket.

Lee, after struggling in the first two games, dismissed captain Graeme Smith in the third over of the South African innings and took wickets at important times to earn the man of the match award.

His figures were spoilt when he conceded 15 runs in his final over, with South African number ten batsman Roger Telemachus slogging two sixes.

Australia needed the win after they lost the first two of five matches while Ponting was missing because of an abdominal strain.

"We've been in this sort of situation before in series. We lost the first final of the VB Series a few weeks ago (against Sri Lanka in Australia) and won the next two," said Ponting.

"It was a really good win for us. We batted steadily enough to post a good total and then Brett and the rest of the bowlers did a good job for us."

South Africa skipper Graeme Smith said he was disappointed with the outcome.

"We needed one good partnership in our top five," said Smith.

"It was a definitely gettable total. Polly and AB showed what was needed."

Smith sent Australia in to bat because he believed the conditions would remain similar for both innings in a day game on a small ground which has yielded some high totals.

A slow pitch proved less batsman-friendly than expected, however.

The Australian batsmen struggled to time the ball against accurate bowling, while South Africa fielded well, but Australia managed to score 99 runs off the last 12 overs. Michael Hussey hammered 22 off 10 balls with two sixes and a four.

Ponting started slowly, taking 48 balls to score his first 24 runs, but accelerated to reach his half-century off 72 deliveries.

The Australian captain launched an assault against key South African bowler Pollock in the 39th over, hitting two boundaries, but he skied an attempted big hit in Pollock's next over and was caught at deep midwicket.

Pollock, who earlier had Adam Gilchrist caught behind for 25, finished with two for 45.

Ponting put on 63 for the second wicket with Simon Katich, who was run out for 49 by outstanding fielding by AB de Villiers, who dived to his left at mid-on and hit the stumps at the bowler's end from a prone position.

Damien Martyn helped Ponting put on 74 for the third wicket. Martyn made 51.

South Africa were in trouble when Smith's dismissal was followed by that of the in-form Herschelle Gibbs, who was unluckily run out when bowler Stuart Clark deflected the ball into the stumps while Gibbs was backing up.

Their fate seemed sealed when three wickets fell for nine runs before the stand between De Villiers and Pollock brought them back into the game. South Africa needed 67 off 46 balls when Pollock swung and missed against Shane Watson.

De Villiers, who made his first half-century in one-day internationals, was out in the next over when Brad Hogg held a sensational left-handed catch on the long-on boundary, leaping backwards after De Villiers tried to hit left-arm slow bowler Michael Clarke out of the ground.

Australia have won four out of five matches between the sides at St George's Park, including a high-scoring encounter four years ago, when they made 326 for three to achieve what was then the highest successful run chase in one-day internationals.