South Africa will take a 20-run lead into day three of the second Test, after AB de Villiers (74 not out) and Vernon Philander (14 not out) saw their side through to stumps in Port Elizabeth.
The hosts only lost the one wicket in the first session, tailender Kagiso Rabada, but opted to go slow after lunch, putting on only 43 runs in the middle sector.
That saw them lose momentum somewhat, with Australia's bowlers able to chip away at the top order, especially when the ball began to reverse swing after the 50th over.
Pat Cummins (2-55) and Mitchell Marsh (2-26) picked up two wickets apiece, while Nathan Lyon, Mitchell Starc and Josh Hazlewood all helped out with one each.
De Villiers looked in imperious form late in the day, after Dean Elgar (57) and Hashim Amla (56) had earlier ground out half centuries.
The Australians will need quick wickets on day three to keep South Africa's lead manageable.
