South Africa hit back with two wickets after Australia's second-string pace attack dismissed the Proteas on a dramatic opening day of the third and final Test at the WACA Ground on Friday.
After winning the toss and electing to bat, the Proteas were bundled out for 225 despite more heroics from Adelaide Test hero Faf du Plessis in a match that will decide the top-ranked nation in Test cricket.
However, the Proteas quickly struck back with a vengeance, claiming two Australian wickets in the hour before stumps.
Opener Ed Cowan was caught in slips by Jacques Kallis off pace spearhead Dale Steyn for a first-ball duck, before Shane Watson (10) was given out lbw to Vernon Philander on a decision review, after umpire Asad Rauf had turned down the initial appeal.
At the close, the home team was 33 for two, with David Warner on 12 and night watchman Nathan Lyon surviving a torrid examination from Steyn in the final over of the day to be seven not out.
Batting at number seven, second Test hero du Plessis again played a lone hand in the South African first innings with an unbeaten 78 off 142 balls that helped add vital late runs after they had slumped to 75 for six when they lost five wickets for 14 runs either side of lunch.
Australia were forced to completely revamp their fast bowling line-up for the match, with their three pacemen from the drawn Adelaide Test -- Peter Siddle, Ben Hilfenhaus and James Pattinson -- all ruled out.
Left-armer Mitchell Johnson was recalled for his first Test in 12 months, Mitchell Starc was promoted after being 12th man for the first two matches in the series, and John Hastings was handed his Test debut.
All were in the wickets as they decimated the South African top order.
It was the returning Watson (1-22) who claimed the initial breakthrough, having Graeme Smith caught at first slip by rival skipper Michael Clarke for 16.
Watson made a welcome return from a calf problem, having missed Australia's last eight home Tests with various injuries, by finding a thick outside edge from Smith to remove the Proteas skipper.
Just before lunch, Starc (2-55) struck two telling blows.
Starc removed opener Alviro Petersen (30) when he bowled the right-hander with a full delivery and then found a way through the defence of Kallis (2), who overcame a hamstring injury to take his place in the match, with a similar ball.