South Africa steady after Clarke ton

South Africa 1 for 125 (Kallis 36*, Amla 30*) trail Australia 445 (Clarke 138, Johnson 64, Harris 3-84, Steyn 3-95) by 320 runs
Scorecard and ball-by-ball details
How they were out

If the first day at the SCG was déjà vu then the second was déjà vu all over again. Michael Clarke's tenth Test century and some vigorous tail-wagging put Australia on top before their bowlers landed a couple of late blows - one to the scorecard and one to a body part - to ensure they retained a slight advantage. Hashim Amla and Jacques Kallis guided South Africa to stumps without further damage and they trailed by 320.

The loss of their captain Graeme Smith to a finger injury hurt but Smith has instilled a sense of fight in his team on this tour. In both the Perth and Melbourne Tests Australia finished the second day clearly in the stronger position only to watch on helplessly as South Africa controlled the second half of the matches. It is a trend Ricky Ponting's men must aim to stop over the coming days.

South Africa's one-down was effectively two-down after Smith retired hurt on 30, in severe pain due to a knock on his left little finger from a Mitchell Johnson delivery that jagged back and bounced sharply. Already nursing a right elbow problem so severe that by his own admission he can barely brush his teeth in the morning, Smith headed to hospital for x-rays.

The out-of-sorts Neil McKenzie was trapped lbw by Peter Siddle for 23 but the question for Australia was whether their attack - their five main bowlers entered the game with 23 Tests' experience between them - had the firepower to ensure a first-innings lead. Siddle was threatening and Doug Bollinger found some edges that didn't go to hand but Amla and Kallis were largely unruffled in their 49-run stand.

Of course, Australia's bowlers couldn't be blamed for being tired later in the day - between them and Clarke they had batted for nearly two sessions to cover up Australia's top-order problems. Siddle and Nathan Hauritz put the finishing touches on Australia's 445, which was their highest total of the series, but the real saviours were Clarke and Johnson.

Their 142-run seventh-wicket partnership brought back memories of Andrew Symonds and Brad Hogg adding 173 for the same wicket at the same venue last year. Australia were in a similar position then, only to watch on as India went beyond 500.

This time the final four pairs combined for 208 and made South Africa pay for some uncharacteristically sloppy fielding. Clarke had been put down twice on the first day and Kallis grassed one at slip when Johnson was on 18. They were chances that proved costly as Clarke showed the fine form that has helped him average 60 in Tests over the past 12 months.

He used his feet effectively against the spin of Paul Harris and was strong off the back foot, also scoring with classic drives and the sort of wristy flicks that are not typical of Australian batsmen. Clarke brought up his first Test century at his home ground with a hasty single to mid-on that nearly had him run-out for 99; he set off in celebration even as the third umpire was called.

Clarke has grown enormously since being handed the vice-captaincy and led from the front in rescuing an innings that had faltered on day one. Only when JP Duminy was asked to bowl his first over in Test cricket did Clarke finally fall for 138. A full toss was driven back to Duminy, whose return catch temporarily left him with the enviable Test averages of 108.50 with the bat and 1 with the ball.

South Africa's main bowlers weren't struggling quite to the extent that Australia's attack was in Melbourne, when Michael Hussey made a similar partnership-breaking strike, but nor were they at their best. Dale Steyn was used sparingly due to a bruised heel and the other fast men lacked incision.

They had problems containing Johnson, whose reputation as a troublesome lower-order batsman grew with his innings of 64, his highest in first-class cricket. Johnson was especially powerful off the back foot and drove viciously through the off side. Even after Johnson edged to slip off Steyn, Hauritz and Siddle (23) continued to create concerns for South Africa's wearying attack.

Their 59-run stand featured some strong drives and deft glides through the cordon from Hauritz, whose 41 was his Test best. It helped Australia to their first 400-plus total of the series but they will need further tweaks to the familiar script on the remaining three days to hold on to their No. 1 ranking.