Mitchell Starc offered Australia a lifeline with an inspired spell after a record low home total against South Africa on an opening day of carnage in the second Test in Hobart on Saturday.
The left-arm pace spearhead put the brakes on the Proteas with three wickets in 10 balls post-tea after the Australians were skittled for 85 off 32.5 overs.
The tourists reached stumps at 171 for five and pushed their lead to 86. Temba Bavuma was unbeaten on 38 with Quinton de Kock on 28.
Up until Starc's intervention South Africa had seized control with a total of 15 wickets tumbling for 256 runs under cloudy skies.
Vernon Philander powered the Proteas with five for 21 as Australia folded to their lowest total at home against South Africa to revive memories of recent batting collapses.
The capitulation revisited the nightmares of their miserable 47 in Cape Town in 2011 and England's demolition of them for 60 last year.
Skipper Steve Smith provided backbone with his unbeaten knock of 48.
"It was a bit of a reminder of Trent Bridge the way the ball was going around. At the end of the day 85 is not good enough from an Australian cricket team," coach Darren Lehmann lamented.
SCORES IN BRIEF
AUSTRALIA: First innings 85 all out (Smith 48 not out; Philander 5-21, Abbot 3-21)
SOUTH AFRICA: First innings 171 for 5 (Amla 47, Bavuma 38 not out; Starc 3-49)