Jondo then hit Lion for two sixes. Cummins messed up the stumps of this batsman who scored 39 runs in a great yorker. Kyle Verena was his victim a little later in this brilliant spell. He was caught at slip for 19 runs.
Marco Jansen (10*) and Simon Harmer (6*) spent the rest of the day.
3 wickets for Cummins, 2 for Helgewood for equal 29 runs.
Australia has already clinched the series by winning the first two Tests. Challenge to avoid whitewash faces South Africa in final days.
Summary Score:
Australia 1st Innings: Decline 475/4 in 131 overs.
South Africa 1st Innings: 149/6 in 59 overs (Elgar 15, Eruya 18, Klassen 2, Bavuma 35, Jondo 39, Verena 19, Jansen 10*, Harmer 6*; Hazelwood 12-3-29-2, Cummins 14-5-29-3, Lion 25-8-65-1, Agar 7-1-19-0, Head 1-0-6-0