Sportal.co.nz 29.Sep.2013Getty Images
The Springboks made it four wins from five Rugby Championship matches this year with the comfortable triumph in Cape Town as Adriaan Strauss, Zane Kirchner and Willie Le Roux all crossed for tries.
South Africa will now fight for the championship against the Kiwis in Johannesburg next Saturday.
The match was decided in the first half as South Africa's powerful forward pack proved pivotal.
The Wallabies took an early lead thanks to a Christian Lealiifano penalty but their advantage did not last long as Morne Steyn responded with one of his own.
A charge from Eben Etzebeth set up South Africa's first try, with Fourie du Preez's neat pass setting up Strauss to barge over.
And just two minutes later the home crowd were celebrating again as JJ Engelbrecht's clever run set up Kirchner, who went past Israel Folau and added to the Springboks' lead.
Steyn kicked two further penalties as South Africa took a 23-3 lead at half time and Wallabies coach Ewen McKenzie responded by addressing his players in the middle of the field.
That delighted the South African crowd and although Australia improved after the break, both defensively and going forward, the damage had already been done.
Flip van der Merwe and Duane Vermuelen were given yellow cards in the second half for South Africa but they still managed another try when Le Roux was too good for Chris Feauai-Sautia and charged over in the corner.
Feauai-Sautia responded with a late try for Australia but it mattered little as Du Preez led the Springboks to another triumph.