South Africa thrashed Australia by six wickets to take a 1-0 lead in their three-match one-day international series at Perth Stadium on Sunday.
Australia made a terrible start to their bid for only a third win in their last 14 matches in the format, reduced to eight for three early on and dismissed for 152 in just over 38 overs.
The Proteas lost openers Quinton de Kock (47) and Reeza Hendricks (44) after a good start but skipper Faf du Plessis (10 not out) and David Miller (two not out) reached the victory target inside 30 overs.
Australia, who will defend the 50-overs World Cup in England next year, were desperate for a morale-boosting win after a miserable nine months for the sport Down Under since the ball-tampering scandal in the test series in South Africa.
Proteas veteran bowler Dale Steyn took the man of the match award for his two wickets for 18 runs.