Second Test, Melbourne, day two (close):
Australia 394 v South Africa 198-7
Peter Siddle had a dramatic impact at the top of the South African innings
Australia had a near-perfect second day in the Melbourne Test to gain a clear ascendancy over South Africa.
After losing in Perth, and reaching a precarious 280-6 on day one on a true wicket at the MCG, they ended up with 394 and then had South Africa 198-7.
Local paceman Peter Siddle took 3-24 and only the prolific Graeme Smith (62) resisted for any length of time.
Australia's Michael Clarke had earlier finished with a fine 88 not out, with Dale Steyn picking up 5-87 in 29 overs.
Siddle, a 24-year-old Victorian, bowled 13 high-quality overs in front of an enthusiastic home crowd, and his contribution was as important as the runs of Clarke and Ricky Ponting - who scored a vital 101 on the first day.
Steyn gained three breakthroughs before lunch but by the end of the day the 114 runs Clarke had helped garner from Australia's lower order in that session was the most important early development.
From there they controlled the South Africans in a style reminiscent of the days of Glenn McGrath, Adam Gilchrist and Shane Warne.
Smith followed his 108 in Perth with a committed 62 - in a calendar year that has netted him nearly 1,600 runs already - but lost his wicket weakly when driving at a wide half-volley and edging behind.
The dismissal forced South Africa to survival mode and left JP Duminy - who reached a calm 34 at the close - to protect the lower order.
Clarke (36 not out) was batting with Brett Lee when the day began - and Australia were positive from the word go.
Lee carved five boundaries in his 21 before driving at Steyn and nicking to slip before Mitchell Johnson edged onto his stumps.
All the time, Clarke was seeing the ball well, scampering ones and twos and adding in the odd boundary as he added a further 26 for the ninth wicket with Nathan Hauritz and 42 for the 10th with Siddle.
He perhaps deserved a century but was left stranded when Siddle was finally dismissed by Jacques Kallis.
The home side had seized the momentum and were not about to give it back.
Using the lunch break as a vehicle to plot their assault on South Africa's batsmen, they gained the first wicket when out-of-form opener Neil McKenzie was beaten for pace and bowled by Siddle with the 10th delivery of the innings.
Hashim Amla contributed just 19 before spearing Johnson straight to Andrew Symonds at gully and an ominous 63-run stand between Smith and Kallis was ended on the stroke of tea.
This was a particularly weak dismissal for South Africa at a crucial stage, Kallis sweeping at the off-spin of Hauritz and getting the shot all wrong to give a simple catch to wicketkeeper Brad Haddin.
Four further wickets fell in the final session. First Smith, perhaps affected by his elbow problems, stretched out to play at a wide one and paid the penalty.
He will attempt to battle through this Test and the probable decider in Sydney before assessing the injury, but currently requires regular painkilling injections. One-day specialist Vaughn van Jaarsveld has been added to the Test squad to cover for Smith and Ashwell Prince (broken thumb).
We probably need to bowl the same way we do to their recognised batsmen instead of looking at the glory ball that knocks tailenders over
South Africa coach Mickey Arthur
Once Smith had departed, AB de Villiers limped to a nervous seven before Siddle nipped one back to bowl him, and Mark Boucher then presented Hauritz with another soft wicket.
Morne Morkel did well to hit 21 but when Johnson bowled him six overs from the finish South Africa had still not saved the follow-on.
Though Duminy did eventually help them creep past the milestone of 195, Australia are red-hot favourites to level the series now.
South Africa coach Mickey Arthur said: "Australia bowled with a lot of passion and high intensity - they really wanted it and put us under a lot of pressure.
"They executed their plans really well against us, and made run-scoring quite difficult.
"[Losing Kallis] was a huge blow, it was disappointing. I felt there were a couple of soft dismissals today but that comes from pressure being created."
He said his bowlers had got their strategy wrong against Australia's lower-order batsmen.
"We have done a bit of homework on them and the thing we have found is that they are batters.
"We probably need to bowl the same way we do to their recognised batsmen instead of looking at the glory ball that knocks tailenders over."
Siddle outshone Lee (0-68) with the ball, but was modest about his achievements.
"[Lee] bowled well, he bowled good lines. He bowled well to the left-handers with not a lot of success. I suppose days like that are going to happen," said Siddle.
"Brett and I did that in Perth and Mitch got the wickets and today we've all bowled well again and the wickets were shared.
"There's going to be plenty of days like that but he's bowling well and bowled good areas. [It was] good team bowling."
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.