Mitchell Starc claimed his 20th five-wicket haul as South Africa collapsed from 203-1 to 329 all out on day one of the decisive third and final Test against Australia at Newlands.
The Proteas were 192-1 at drinks in the second session after Australia had won the toss and opted to bowl, with Marques Ackerman 95 off 94 balls.
Aiden Markram scored 78 and David Bedingham made 50 before the middle-order collapsed, as Starc took 6-72 - his best figures against South Africa in Tests - to fashion a turnaround.
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Markram and Ackerman had put on 140 by lunch, with Australia looking clueless after having made four changes to the side - including dropping opener Nic Maddinson and having veteran Steve Smith ruled out through injury
Ackerman was stumped for 95 off Nathan Lyon after charging the off-spinner, having hit 12 fours and two sixes before falling short in his bid for his maiden Test century.
Markram - dropped off Starc in the morning session - added 45 with Bedingham as South Africa moved to 203-1, then Starc pulled off a stunning catch at square leg to dismiss Markram off Josh Hazlewood.
Lyon bowled skipper Temba Bavuma for a three-ball duck and left-arm spinner Cooper Connolly picked up his maiden Test wicket, as he trapped Matthew Breetzke lbw for two.
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Starc removed Bedingham after tea and had Wiaan Mulder caught behind two balls later for a duck, with South Africa losing five wickets for just 29 runs before Marco Jansen (52) and Ryan Rickelton stemmed the tide.
Jansen scored a second successive half-century and Rickelton made 42 as the pair added 95 for the seventh wicket, only for Starc to strike again with the second new ball to rip through the tail.
Starc had Rickelton lbw in the 81st over and two balls later bowled Jansen, then made it four wickets in six balls when he bowled Gerald Coetzee for a golden duck and removed Kagiso Rabada for another nought.
South Africa plunged from 327-6 to 329 all out to hand momentum back to Australia, who won the first Test in Durban by 214 runs before being thrashed in the second by an innings and 31 runs in Gqeberha.
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