Ricky Ponting century covers for Australia's failings

Captain's knock: Ricky Ponting's century held together the Australian innings on day one of the second Test at the MCG

Australia captain Ricky Ponting scored a superb Boxing Day century at the MCG, but South Africa continue to make the running in this riveting series

Pilloried in the Australian media for his captaincy at Perth, Ricky Ponting responded with a feisty, angst-fuelled century. It was a thunderous innings, studded with booming drives, and for most of the afternoon he seemed to have the South Africans at his mercy. But when he fell, his team began to crumble. Australia were a shaky 280 for six by the close.

Increasingly grim-faced and gimlet-eyed, Ponting is starting to resemble another captain who led from the front - that 1980s icon Allan Border. The founder of Australia's recent dynasty, Border began his 10-year reign with a scrappy sort of side: a mixture of naïve newcomers and ageing has-beens, who could not even be relied upon to beat the Poms. Ponting now finds himself in a similar boat, and is even beginning to wear Border's familiar put-upon look, if not the trademark moustache.

Australia do still have plenty of talent in the ranks. Their recent discoveries include Mitchell Johnson, arguably the fastest bowler in the world, as well as the clean-hitting batsman-wicketkeeper Brad Haddin. But there are also some major structural problems to be addressed. As with so many struggling teams, the senior players are not pulling their weight, which makes it so much harder for the juniors to establish themselves.

Here at the MCG, the cracks began showing within half-an-hour of the start. Matthew Hayden, Australia's one-time enforcer, scooped the first half-volley he received to backward point. It was a shot of a man who is uncomfortable with his own game. Now, if Hayden does not produce in the second innings, he will leave the selectors facing a difficult decision. Do they stick by him for the Sydney Test, in the knowledge that he is a virtual passenger at present? Or do they bring a distinguished career to a close?

Ponting took over from his old friend and ally, and looked almost as uncomfortable early on. On 24, he could not decide whether or not to play at a widish ball from Dale Steyn, with the end result that he steered it to third slip. The ball seemed to travel in slow motion - too slow, Ponting later suggested, for Neil McKenzie, who made a mess of a simple chance. It was the first catch that has gone down in the series, and it turned out to be an expensive one.

Freed up by his reprieve, Ponting went on the rampage when the teams emerged after lunch. As the adrenaline surged, his personal run-rate immediately ratcheted up from just over 2.5 to a little over six. A glorious punch down the ground from the first ball after the interval was followed by a driving masterclass - three boundaries in three balls from Makhaya Ntini - as the ball was dispatched to all points of the compass. A 60,000-strong crowd rose to salute his second century on Boxing Day, the blue-riband occasion of the Australian sporting calendar. Both have come against South Africa.

Ponting's mastery was in sharp contrast to the struggles of his team-mates. Simon Katich ground his way to 54 before missing a straight one. Mike Hussey, whose statistics are becoming less Bradmanesque by the minute, was caught in an agony of indecision by a ball from Steyn, and flicked a thin edge through to the wicketkeeper. After successive scores of 0, 10 and 0, the man known as Mr Cricket is in danger of becoming Mr Nick-it.

Ponting fought on until just before the tea-break, when he pushed forward to Paul Harris's surprisingly effective left-arm spin and was held at short-leg. The final session was left to Michael Clarke, whose 36 not out occupied the best part of four hours, and a couple of contrastingly breezy cameos from Haddin and Andrew Symonds. South Africa were the happier team by the close.