Australia survived an early scare to make a solid start after South Africa won the toss and put them into bat in their opening one-dayer at the WACA Ground on Friday.
Opener Aaron Finch was given out leg before wicket to Proteas paceman Dale Steyn for just one.
However, the decision was subsequently overturned by the third umpire.
And with David Warner looking confident on 29 off 30 balls, the home side reached 48 for no loss in the ninth over.
Finch was on 12 from 22 balls.
It is the first game of a five-match series, with Australia winning the preceding Twenty20 series between the countries 2-1.
The home side left out all-rounder Steve Smith, naming him 12th man.
South Africa named Rilee Rossouw to carry the drinks.
Teams: Australia – Michael Clarke (C), David Warner, Aaron Finch, Shane Watson, Michael Clarke, George Bailey, Mitchell Marsh, Glenn Maxwell, Matthew Wade, Mitchell Johnson, Nathan Coulter-Nile, Josh Hazlewood.
South Africa – AB de Villiers (c), Quinton de Kock, Hashim Amla, Faf du Plessis, Farhaan Behardien, David Miller, Ryan McLaren, Vernon Philander, Dale Steyn, Morne Morkel, Imran Tahir.
Umpires: Simon Fry (AUS), Nigel Llong (ENG)
TV Umpire: Brent Bowden (NZL)
Match referee: Javagal Srinath (IND)