The tourists took a one-run lead thanks to four fifty-plus scores from a recast top six
Match Report:
ScorecardInglis shines as Aussie top-order puts Proteas to sword
Australia's successful navigation of the Cape Town's glorious twilight, after the same period sparked South Africa's implosion 24 hours earlier, allowed the visitors to take tentative control of their series decider.
The adaptability of the series' runaway leading run scorer Matthew Renshaw in his first innings back as an opener ensured the middle-order he has left behind, and which is without its star operator in Steve Smith, could thrive in prime Newlands batting conditions.
After Cameron Green (65 off 110) posted his third fifty-plus score from as many Test innings, the enterprising Josh Inglis (85no from 111) and the more watchful Alex Carey (50no from 126) took the Aussies to a commanding 4-330 by stumps.
Marnus Labuschagne's duck was the one sour note in an assured effort that has given Pat Cummins' men a one-run lead at stumps on day two.
Where the Proteas had lost 4-2 to Mitchell Starc's devastating second new-ball swing, Inglis and Carey accelerated in admittedly better light than the previous evening. Table Mountain shielded the pair of wicketkeepers from the fading sun in a union that was worth 145 by the close.
Forty-four of those came after South Africa made the unsuccessful switch to a harder ball, flattening an attack that had relied on the spirit of Marco Jansen (2-37) and Simon Harmer (2-84) for penetration. A bout of stomach cramps goes some way to explaining the ineffectiveness of Kagiso Rabada (0-81).
But it was a big tick for a touring batting unit reformed due to Smith's neck injury. The fit-again duo of Green (back from an abdominal strain) and Inglis (batting with a splint protecting his broken index finger) made strong impressions in their respective entrances to the series.
Travis Head (41), accompanied again by Renshaw in what marked his fourth switch of opening partners from Australia's past five Tests, could hardly have asked for a better platform to add another big score after his fourth-innings century in Gqeberha.
But having torched South Africa's high-velocity seamers through the morning session, the left-hander succumbed to perhaps the gentlest delivery he saw, chopping on to his stumps off Harmer - the sixth time in Head's past 14 international innings he has been out in that fashion.
It had taken one delivery for the off-spinner to continue his stellar series; he needed a further five to weave a spell on Labuschagne, whose lead-footed prod was nicked to slip and sent a delirious Harmer into frenzied celebrations.
The veteran, whose quiet displacement of seasoned fellow spinner Keshav Maharaj has proved a selection masterstroke, might have considered himself unfortunate not to then have a sweeping Renshaw out on review, the left-hander spared by the 'umpire's call' on height.
In a team that prizes versatility, Renshaw's neutering of the new ball after eviscerating the hosts' spinners in Durban is sure to have won him fans among the team's brains trust here having had an indifferent return to the opening spot in Mackay against Bangladesh in August.
He ignored the short ball as he ticked past fifty, a ball after Green had done likewise, leaving or defending the dozen bouncers South Africa aimed at him.
Green took the opposite approach, at one point hitting Rabada for consecutive sixes, the second fortunate not to find a fielders' hands given it was the diminutive Marques Ackerman attempting the boundary-line catch instead of Jansen.
As has been the case all series, however, the gigantic SA allrounder is never far from the action. Renshaw sparred at an upper-cut and stood like a church mouse as the hosts' appeal was turned down. He walked as soon as the big screen confirmed the thin edge.
Green had taken 14 balls to get off the mark. Where his early nerves might once have proved terminal, he moved into his innings with fluency - with some good fortune when a nick to Harmer was deemed not to have carried.
But after slapping Jansen's final ball before lunch over wide mid-off, his willingness to flirt in the channel against the extra bounce of Jansen led to his downfall.
Two balls into the Jansen over after Renshaw had been dismissed, Green fended at one angled across him, edging to an unsighted Harmer standing at a wide slip. He somehow pouched the catch between his legs as if trapping a mosquito in the dark.
Inglis survived several hairy moments, nearly barbecuing Carey on a 'yes, no' run call and surviving a Harmer turner that looped perilously close to the top of his stumps.
The pair put their early miscommunication behind them as they later hared between the wickets, with Carey content to move to his slowest Test fifty (125 balls). Inglis meanwhile reverse-swept with abandon, cannily using the stroke to toy with Harmer after launching him for six over mid-wicket as he galloped towards a second Test hundred.
Qantas tour of South Africa 2026
All matches to be broadcast exclusively in Australia on Kayo and Fox Cricket
First Test: Australia won by 214 runs
Second Test: South Africa won by an innings and 31 runs
Third Test: October 27-31, Newlands, Cape Town, 7:30pm AEDT (10:30am local)
South Africa Test squad: Temba Bavuma (c), Marques Ackerman, David Bedingham, Corbin Bosch, Gerald Coetzee, Simon Harmer, Marco Jansen, Keshav Maharaj, Aiden Markram, Wiaan Mulder, Senuran Muthusamy, Dane Paterson, Kagiso Rabada, Ryan Rickelton, Tristan Stubbs, Kyle Verreynne
Australia Test squad: Pat Cummins (c), Scott Boland, Alex Carey, Cooper Connolly, Cameron Green, Josh Hazlewood, Travis Head, Josh Inglis, Matthew Kuhnemann, Marnus Labuschagne, Nathan Lyon, Michael Neser, Matthew Renshaw, Steve Smith, Mitchell Starc, Beau Webster