South Africa have amassed an imposing first-innings total of 488 on day two of the fourth Test, further demoralising a depleted and distraught Australia side in Johannesburg.
The Proteas resumed at 6-313 on Saturday morning, with Pat Cummins and debutant Chadd Sayers having led a formidable fightback late on day one.
Pint-sized batsman Temba Bavuma proceeded to sap any confidence Australia artificially created overnight, finishing 95 out after he was dropped by Joe Burns when on 61.
Cummins grabbed the second five-wicket haul of his Test career, dismissing Keshav Maharaj and Morne Morkel in his first over of the post-lunch session to end an innings that spanned 136.5 overs.
The Proteas hold a 2-1 series lead, with history suggesting they've already wrapped up the nation's first home Test series win over Australia since the end of apartheid.
No Test team have ever batted first at the Wanderers, posted 400 or more then lost.
New captain Tim Paine admitted on Friday night that "a lot of the guys were thinking about some other things or were a little bit flat", referring to the cheating scandal that led to three suspended teammates returning home in shame.
Openers Matthew Renshaw and Burns, who flew in after helping Queensland lift the Sheffield Shield in Brisbane on Tuesday, were understandably jet-lagged in the field.
Cummins and Josh Hazlewood were dealing with the toll of playing every Test since the start of the Ashes last November, an intense stretch of big workloads.
Hazlewood and Cummins, who have already delivered a combined 54.5 overs in the current match, continued to toil for scant reward on day two.
Nathan Lyon snared the only wicket to fall in Saturday's morning session, when a loose stroke from Quinton de Kock resulted in a simple catch for Mitch Marsh at mid-on.
Lyon finished with 3-182 from 40 overs.
Only once before, when he was taken for 3-215 from 47 overs in Chennai, has the offspinner has conceded more runs in a Test innings.
Paine suffered a painful blow to the thumb early in the session while standing up to the stumps to Sayers. However, he continued to keep.
There was plenty for outgoing coach Darren Lehmann to like about the visitors' effort but they're at risk of being badly outclassed if a couple of batsmen don't stand up in the absence of suspended superstars Steve Smith and David Warner.