Russell Crowe was in the stands as Ricky Ponting accepted a huge ovation for his 27th Test century like an all-conquering gladiator. With arms aloft and the moment standing almost as still as the batsman, Ponting held his weapon in one hand and helmet in the other, a pose similar to Crowe's triumphant character Maximus in the Hollywood film. It was a day for an A-list performance: Ponting was in his 100th Test and Australia were in more trouble than a freshly captured slave.

Looking at Ponting, it was impossible to tell his side's predicament. Three for 54 at the beginning of the day could have been 3 for 400 and it is one of his many strengths that his batting demeanour is not usually dictated by the scoreboard. Runs flowed at a rate thought to be impossible after the first two days - his fifty came from 68 balls; his hundred from 143 - and Ponting entertained with his pulling, driving and attitude in ripping his side out of severe trouble and towards the follow-on mark.

Sydney is a grand ground for big occasions and the stars and spectators turned up to discover how Ponting would steer his side. He does it best as a batsman and the performance was suitable for the eyes of Heath Ledger, a big-name thespian whose roles include Ned Kelly, another Australian hero. Cricket's headliners were also overshadowed by a man who acts as one of the modern-day greats.

Ponting's celebration match began with a lost toss, a dropped slip catch and his bowlers being taken for 451, but he improved it by passing Mark Waugh's 8029 Test tally, moving him to third on his country's list of run-scorers, and finished sitting alongside Allan Border on the century table. Border waited 150 matches for his 27th hundred and now Don Bradman and Steve Waugh are the only Australians ahead of Ponting.

Showing few signs of discomfort until reaching the 90s, Ponting survived an edge between a poorly-spaced slip cordon and received an lbw reprieve from Aleem Dar on 95 - one of three bad decisions from Dar today; two favoured Australia - but he squinted his eyes, regained his focus and reached the milestone with a two from a misfield. Another exclusive party was joined as he became only the sixth player behind Colin Cowdrey, Gordon Greenidge, Javed Miandad, Alec Stewart and Inzamam-ul-Haq to post a century in their 100th Test.

Thoughts of further records were ended by Ponting's dismissal to a Jacques Kallis inswinger and a mini-collapse of 3 for 4, which had Australia suffering at 7 for 226. Ponting thrust his bat against his pad in frustration after his dismissal for 120 and his worries at giving up a relatively healthy position were real.

Andre Nel, who was South Africa's finest with 4 for 81, steamed away and was on a hat-trick as wickets fell in a cluster again, and it took Adam Gilchrist's blockbusting 86 to ease the team's major problems. Their fears were downgraded the longer he stayed.

A box-office favourite who has been worryingly out of form, Gilchrist started tentatively and gradually moved towards his regular touch in valuable partnerships of 59 with Stuart MacGill and 37 with Glenn McGrath. After reaching fifty, his powers of intimidation returned and he unleashed some crashing drives, including a six over cover off Shaun Pollock, and spectacular thumps to midwicket.

With ten fours, two sixes and clever farming of the strike, Gilchrist provided the ideal second screening for the home side and the first-innings deficit, which threatened to hover around 200, was cut to 92. The day was still Ponting's, but he was thankful for the contributions from his lower-order support cast. Australia must be careful not to fluff their lines further over the next two days as they attempt to win the series.