Second Test, Melbourne, day one (close):
Australia 280-6 v South Africa
Ricky Ponting looked in supreme form against the South Africa attack
Ricky Ponting struck an assured 37th Test century but South Africa reduced Australia to 280-6 after the opening day of the Boxing Day match at the MCG.
He chose to bat first but out-of-form Matthew Hayden made just eight before skewing to point in the eighth over.
Ponting was dropped at slip on 24 but went on to hit 10 fours and a six, sharing 121 with Simon Katich (54) before falling at short-leg for 101.
Michael Clarke was 36 not out but Brad Haddin fell in the penultimate over.
It was Ponting's 17th hundred as captain and his fourth in Melbourne, and was badly needed as his side endeavour to reverse a 1-0 deficit in the three-match series.
Hayden has an even better record at the MCG, with a remarkable six centuries in his last seven Tests at the ground, but his miserable recent run of form continued.
In six innings in home series with New Zealand and South Africa, the 37-year-old left-hander has made only 56 runs.
He thumped one boundary over mid-off off Dale Steyn in the third over, but drove loosely at one angling well wide of off-stump from Makhaya Ntini and was smartly caught by JP Duminy.
Ponting took 24 balls to get off the mark, but did so in style by hooking Morne Morkel over fine-leg for six.
In the final over before lunch the skipper pushed forward at Steyn and was fortunate Jacques Kallis was off the field and Neil McKenzie had deputised in the slip cordon.
AB de Villiers moved to second slip to cover for Kallis so the opportunity at third slip fell to McKenzie, but he fumbled the chance and could not hold on with his second attempt as the ball slid to the turf.
Ponting quickly ensured that the tourists would regret the error, passing fifty with three successive fluent drives to the boundary off Ntini.
Katich also looked in good touch, but having recorded his 12th Test fifty he got an inside edge at one angling in from Steyn and the ball crashed into the timbers.
Mike Hussey lasted only nine balls before he attempted to leave one from Steyn outside the off-stump but the ball brushed the toe of the bat as he raised it and went comfortably through to wicketkeeper Mark Boucher.
It was the left-hander's third duck in his last five Test innings, and in the final over before tea, Ponting was caught off bat and pad prodding forward, a triumph for left-arm spinner Paul Harris, who had just moved Hashim Amla into the short-leg position.
When Andrew Symonds slashed wildly and was superbly caught two-handed by Kallis diving to his right at slip, the Australians were 223-5.
Haddin struck some positive shots in partnership with Clarke, but the South Africans were determined to restrict the scoring and their tactic was rewarded when the wicketkeeper drove away from his body and was smartly snaffled by Graeme Smith at first slip.
That gave Ntini his 376th Test wicket, putting him level with the late, great West Indian paceman Malcolm Marshall, an inspiration for the South African in his formative years.
"He has always been my hero and I modelled my action on him after I had to change it through injury. Unfortunately I never got the chance to see him in live action but he has been a wonderful role model for me and this means a great deal to me.
"To emulate your hero means that you are going somewhere with your life and I hope I can now get to 400 wickets as quickly as possible."
The world's three leading news agencies are not covering the series due to a dispute with Cricket Australia.
Reuters, Agence France-Presse and Associated Press have suspended all coverage of the 2008-09 season.
Their photographers and reporters did not supply material from within the ground. As a result, we cannot use pictures from the current match.