Pat Cummins produced a devastating spell of six for 28 to bowl South Africa out for 138, but Australia's own batting collapse left the World Test Championship final on a knife-edge at Lord's. The hosts, after taking a 74-run lead, were reduced to 144 for eight by the close, leading by just 218 runs.
Cummins, who became the eighth Australian to claim 300 Test wickets, was the architect of South Africa's demise, with his post-lunch burst of four for four in 4.1 overs the defining passage. Temba Bavuma made 36 and David Bedingham 45, but the Proteas lost their last five wickets for 12 runs.
South Africa roared back, however, with Lungi Ngidi taking three for 35, including the scalps of Steve Smith and Beau Webster. Kagiso Rabada made early inroads, while Marco Jansen and Wiaan Mulder also struck as Australia slumped to 73 for seven.
Alex Carey's gritty 43, allied to a 61-run stand with Mitchell Starc, helped Australia recover to 144 for eight. Starc survived a chance at slip, and the match remains anyone's game with 28 wickets falling in just six sessions.
The final showdown, dubbed 'The Ultimate Test', has lived up to its billing, with both bowling attacks exploiting a beige Lord's surface that has offered consistent movement. South Africa will need a far sturdier top-order effort in their second innings to keep their hopes alive.
