Mitchell Starc claimed four wickets in the space of six balls as Australia hit back on the opening day of the third Test against South Africa at Newlands on Tuesday.

Starc ended with figures of six for 72, and South Africa were dismissed for 329 just before stumps in the series deciding match between the two top-ranked Test sides.

South Africa began strongly after Australian skipper Pat Cummins won the toss and sent them in on a pitch which looked ideal for batting.

Marques Ackerman, playing only his second Test, scored 82 off 75 balls, and he and Aiden Markram added 140 without loss before lunch.

Their partnership reached 158 before left-hander Ackerman stepped out to off-spinner Nathan Lyon and was stumped for 95. His innings came off 94 balls and included 12 fours and two sixes.

That dismissal sparked an Australian revival, with six wickets falling for 74 runs in 25 overs.

Josh Hazlewood had Markram caught at long leg for 78, and Lyon bowled Temba Bavuma for a duck. Starc then removed David Bedingham (50) and Wiaan Mulder (0) within three balls.

Ryan Rickelton and Marco Jansen added 95 for the seventh wicket, and South Africa looked set to end the day in a commanding position until Australia took the second new ball shortly before the close.

Starc trapped Rickelton leg before wicket for 42 on the fourth ball with the new ball, and two balls later he bowled Jansen for 52.

He finished the innings in his next over, bowling Gerald Coetzee with the first ball and getting Kagiso Rabada lbw with the third.

Australia went in with four changes for the decider after losing the second Test in Gqeberha by an innings and 31 runs. Steve Smith was ruled out with a neck injury.

Batsmen Cameron Green and Josh Inglis, batting all-rounder Cooper Connolly and off-spinner Nathan Lyon replaced Smith, Nic Maddinson, Beau Webster and Scott Boland.