The Wallabies have failed to recover from a first-minute Kurtley Beale brain explosion, going down 23-12 to the Springboks in Port Elizabeth.
Things couldn't have started worse for the visitors when Beale threw a wild intercept pass in the game's 24th second and South Africa quickly jumped to a 14-0 lead.
Australia recovered and threw a bulk of the second-half punches as they controlled possession and territory.
But, like a fortnight ago in the Gold Coast loss to Argentina, they lacked the polish needed to exploit it and eventually ran out of gas in the face of incredible cover defence.
Rassie Erasmus's side backed up their incredible defensive showing in their defeat of the All Blacks a fortnight ago, making nearly double the tackles of Australia (146-77) and continually shutting down the visitor's expansive forays.
It marked their sixth loss from eight Tests this year and adds further pressure on Michael Cheika and his squad less than 12 months out from the World Cup.
Beale's bewildering 24th-second speculator looked destined for nobody other than Springboks flyer Aphiwe Dyanti, who caught the floating pass just metres from the tryline for a gift five-pointer.
It set the tone for a manic opening 20 minutes in front of nearly 42,000 boisterous fans at Nelson Mandela Bay Stadium.
Australia finally settled, South Africa's Handre Pollard knocking over a penalty for a 20-12 half-time lead.
Cheika's men were rushed and ragged early, but hung on largely thanks to David Pocock's pilfering efforts.
He had three clean steals in the first 40 minutes, steadying the side before Will Genia manufactured some points.
First the scrumhalf cut out two men for the perfect Reece Hodge assist in the corner.
Then he finished a five-pointer created by strong-running fullback Dane Haylett-Petty's bust and offload to make it 17-12 in the 34th minute.
Earlier Faf de Klerk slid through after Pollard broke Folau Fainga'a's tackle to make it 14-0 in the 21st minute.
It could have been worse if not for a match-saving tackle by Marika Koroibete and some Springbok fumbles.
But the Wallabies left points on the paddock too, with Matt Toomua missing one conversion and a penalty and Hodge also putting his long-range penalty to the right of the posts in the first half.
The Wallabies now head straight to Argentina, where they play Los Pumas next weekend in Salta.