Pat Cummins ripped out 3‑54, leaving Australia ahead by 139 runs at stumps on day three in Durban.
A tight Australian attack dismissed South Africa for 284, with Mitchell Starc 2‑63, Josh Hazlewood 2‑54 and Nathan Lyon 2‑58 sharing the spoils.
Matt Renshaw smashed a career‑best 190, steering Australia to 390 after teetering at 124‑6.
Australia’s second‑innings chase stalled at 33‑0 after 5.4 overs; Nic Maddinson 17* and Travis Head 10* saw play halted by bad light, losing nearly 13 overs.
David Bedingham led the hosts with 49 off 73, while a 52‑run ninth‑wicket stand—Keshav Maharaj 34 and Simon Harmer 35*—patched the damage.
The reigning world Test champions, South Africa, beat Australia in the 2025 final; this marks Australia’s first visit since the 2018 ball‑tampering fallout.
Australia’s bowlers turned the tide on day three, carving out a massive lead. For my money, their relentless pressure will decide the series. Will the visitors clinch the match?
South Africa slumped to 115‑4 at lunch, yet Aiden Markram’s 37 and Bedingham’s 57‑run partnership lifted them from 27‑1 the previous day.
Australia broke through just before the drinks break as Markram edged Starc to slip in the 21st over.
The Proteas raced to 59‑1 in the opening hour; later, Temba Bavuma (3) fell to Lyon, with Steve Smith pulling off a sharp reverse‑sweep catch.
Cummins then trapped Bedingham in the slips, Smith snatching another brilliant catch on his left.
Post‑lunch, Cummins struck again, removing Wiaan Mulder, who had 30 off 50 with three fours and a six, after a 56‑run stand with Tristan Stubbs.
Stubbs soon followed, dismissed for 32 at square leg, again by Cummins.
Lyon claimed Kyle Verreynne for 13 at slip, leaving South Africa 197‑7; Marco Jansen then blasted six fours for a rapid 26 before falling to Hazlewood.
At tea, the hosts were 238‑8, with Harmer and Maharaj surpassing the follow‑on threshold; Starc ended the 50‑run stand by dismissing Maharaj.