South Africa moved into a powerful position despite a fightback by Australia and an injury to fast bowler Morne Morkel on the third day of the fourth Test at the Wanderers Stadium on Sunday.
South Africa finished the day on 134 for three in their second innings, an overall lead of 401.
The Proteas, leading the series 2-1, need only to draw to beat Australia in a home series for the first time since 1969/70.
But Australia provided the fight that had been promised the previous evening by bowling coach David Saker.
From a seemingly hopeless overnight total of 110 for six, they added another 111 runs before being bowled out.
South Africa did not enforce the follow on, with doubts about the ability of Morkel to bowl because of a side strain.
Australia`s bowlers then restricted the hosts to a run rate of 2.4 in the second innings.
New captain Tim Paine set the example in the morning. Despite batting with a hairline fracture of his right thumb, he made a defiant 62 before being last man out.
Paine and Pat Cummins walked out to resume the Australian innings on a heavily overcast morning, with their team facing the humiliation of being bowled out quickly and forced to follow on.
But they stayed together for most of the morning, with Cummins making a Test-best 50 off 92 balls before he missed a sweep and was leg before wicket to left-arm spinner Keshav Maharaj shortly before lunch.
Their seventh wicket partnership was worth 99, the best for any wicket by Australia in the series.
Morkel, playing in his last Test before retiring from international cricket, broke down as South Africa toiled in search of a breakthrough, leaving the field two balls into his fourth over of the day.
A South African team spokesman said the injury was in the same area that he damaged in a Test against Bangladesh in October, keeping him out of action for two months.
But after being strapped up, Morkel bowled a few gentle deliveries to coach Ottis Gibson during lunch and took the field with the rest of the team after the interval, giving hope that he may be able to bowl in the second innings, even if it is not at full pace.
South Africa did not attempt to force the pace in the second innings, although Aiden Markram again struck the ball crisply in making 37 off 56 balls.
With a 2-1 lead in the series and only three fully-fit front-line bowlers, South Africa may have wanted not only to build an indomitable lead but to use up time.
Markram`s innings took him to exactly 1,000 runs in 18 innings in his first ten Tests.
The only South African to reach the mark in fewer innings was former captain Graeme Smith, achieved the feat in 17 innings.
The scoring rate dried up, with off-spinner Nathan Lyon gaining turn and bounce from the golf course end, while Cummins again challenged the batsmen with high-quality fast bowling.
AB de Villiers threatened briefly to ignite the scoring rate, but was caught behind when he tried to cut a ball from Cummins that bounced sharply.
Opening batsman Dean Elgar was particularly obdurate, scoring 39 not out off 158 balls.