An Aaron Finch century and four wickets from Mitchell Starc led Australia to a 37-run victory to claim a 2-1 series lead over South Africa in Canberra on Wednesday.
George Bailey won the toss and opted to bat with Australia's top order all putting in strong performances.
Finch (109) knocked up his fifth ODI ton combining with David Warner (53) for a 118 run partnership for the opening wicket.
Shane Watson (40) and Steve Smith (73*) both looked solid with the bat and helped Australia to 329 for the South Africans to chase.
In response, Hamish Amla (102) and Quentin de Kock (47) got the tourists off to a great start putting on a 108 run partnership.
Starc (4-32) and Josh Hazlewood (3-51) put in solid performances for with the ball to put South Africa on the back foot and they were bowled out in the 48th.