Clarke hits an unbeaten 200 for Aussies
Captain Michael Clarke became the first man in Test history to score four double centuries in a calendar year as Australia produced a dominant performance on day one of the second Test against South Africa in Adelaide.
Clarke, who hit 259 not out in the drawn series opener, ended unbeaten on 224 from 243 deliveries, with 39 fours and a six.
Australia's total after 86.5 overs in the day was an imposing 482 for five, with opener David Warner (119) and veteran Michael Hussey (103) also compiling centuries and hitting four sixes apiece.
When Clarke arrived at the crease South Africa, who had lost the toss, were well in the game having struck early to leave the home side on 55 for three.
But while there were failures for Ed Cowan, Rob Quiney and Ricky Ponting, Warner and Clarke led the fightback superbly.
The duo's game-turning stand was surely eased by the injury-enforced departure of Jacques Kallis, not to mention Vernon Philander pulling out before the start of play.
All-rounder Kallis had taken the first wicket of the day, trapping Cowan plumb in front of the stumps and also claiming a return catch after the ball hit the bat - with the latter dismissal taking precedence under the laws of the game.
Morne Morkel then added the wicket of Quiney, caught by Graeme Smith at slip for a duck.
Australia's 44 for two became 55 for three when Kallis removed the clearly out-of-form Ponting for four. The dismissal offered further ammunition to the theory that Ponting is in his final days as an international player, the former skipper mis-reading the length and losing his off stump only to tumble to the ground as he lost his footing.
Yet at the other end Warner was scoring freely and found a willing partner in Clarke as the pair moved the score to 102 by lunch.
The start of the afternoon session was the start of the carnage, Warner taking 10 off the loose Imran Tahir in the first over and then reaching his 100 in 93 balls after another Tahir over leaked 17.
Both batsmen were finding the ropes with abandon by this stage and added a remarkable 99 runs in the first 10 overs after the resumption.
Warner eventually fell, edging Morkel to Smith to halt the partnership at 155, but Hussey wasted no time finding his stride.
Clarke cut Tahir for four just before tea to seal yet another century in a tea score of 280 for four.
South Africa's stretched bowling attack suffered another blow when Dale Steyn left the pitch for treatment for a lengthy period in the evening session and with Tahir and Rory Kleinvedlt looking well short of Test class, Australia cashed in.
They added a stunning 202 runs before stumps, with Clarke smashing Morkel for five fours in a single over to move past 150.
Clarke's now inevitable double hundred came with a single off his 226th ball and when Hussey thrashed the very next delivery, a rank Tahir full toss, for six he joined his skipper to three figures.
Steyn, having returned to the field, finally broke the 272-run partnership when he bowled Hussey with the last ball of the day but it was scant consolation for the Proteas.