Australia came back with five wickets in the final session to stop South Africa's momentum and hold the home team to 263-7 by stumps on Day 2 of the second test on Saturday, a lead of 20 runs.
South Africa was 153-2 at tea - with two batsmen on half-centuries - and heading for a significant first-innings lead at St. George's Park before Mitchell Starc bowled Hashim Amla with a swinging yorker on the fourth ball of the last session to start Australia's comeback.
Amla was out for 56, opener Dean Elgar followed next over for 57, and allrounder Mitchell Marsh picked up two wickets as Australia's bowlers went on a run of four wickets for 28 runs.
AB de Villiers held South Africa together until stumps with 74 not out from just 81 balls, a free-flowing innings with 14 fours that made batting look much easier than it was on a pitch offering heaps of reverse swing.
South Africa is ahead but its position is not as strong as it was hoping for after a strong start. That replicated Australia's first innings, when the tourists were 161-3 and 243 all out in a similar late slump.
Even though Elgar and Amla put on 88 for South Africa for the third wicket, that stand took nearly 3 ½ hours and 278 balls, with batting a grind in the afternoon.
Amla was twice given out lbw by the onfield umpires and twice overturned the decision using the TV review system, surviving first when he was on 7 and again when on 40.
South Africa lost just one wicket in the first session, nightwatchman Kagiso Rabada for 29, and no wickets in the second session, before the late surge from the Aussie quicks.
Starc bowled Amla and Josh Hazlewood had Elgar caught behind eight balls later. Marsh trapped South Africa captain Faf du Plessis and Theunis de Bruyn lbw in successive overs.
Offspinner Nathan lyon also made his presence felt with the wicket of Quinton de Kock for 9. lyon removed de Kock with a wonderful, flighted delivery that turned past the bat to knock back off stump.
Rabada was the chief destroyer in the Australian first innings with 5-96, including a burst of 5-13 off 18 balls.
But after another incident that undermined the cricket, Rabada's participation in the remainder of the series is in doubt.
Australia won in Durban by 118 runs to lead the four-test series 1-0.
Sa officials face action
Two senior Cricket South Africa officials face disciplinary action after posing with spectators wearing masks showing the face of All Black rugby player Sonny Bill Williams during the second Test against Australia.
The masks were likely to have been worn to taunt Australian batsman David Warner, whose wife reportedly had an encounter with Williams in 2007 before meeting Warner.
There have been calls on social media for spectators to wear the masks following a row between Warner and South Africa's Quinton de Kock during the first Test, which Warner blamed was sparked when De Kock insulted his wife.
In a statement issued on Saturday, Cricket South Africa distanced itself from the action of the officials, marketing manager Clive Eksteen and communications manager Altaaf Kazi. Eksteen is a former South African Test player.
The two officials were photographed with three spectators wearing the masks at the match at St George's Park in Port Elizabeth.
The statement said CSA had taken "immediate precautionary steps" against the officials and that there would be an internal disciplinary process.
CSA president Chris Nenzani apologised to the board of Cricket Australia and its officials, team management, players and their families.
The statement urged South African supporters to refrain from "being involved in distasteful or unwelcome actions that may impact the image of the sport and its supporters."
According to the Sydney Morning Herald, the Australian team were "outraged" by a decision to allow the masks to be brought into the ground.