Australia won the toss and elected to bat first
Beth Mooney scored a fluent 53 and forged a dominating 114-run stand with Nicole Bolton for the opening wicket.
Nicole Bolton scored freely and sailed past her half-century to give Australia a fine start
Dane van Niekerk took 2 for 41 in her eight overs to peg Australia back after their strong start.
Ellyse Perry scored a brisk 55 to stabilise Australia in the middle.
Alyssa Healy smashed 16 runs from 10 balls.
Marizanne Kapp's 2 for 26 helped keep Australia in check.
Sune Luus's 5 for 67 in 10 overs helped bowl Australia out for 269 in 48.3 overs.
Laura Wolvaardt gave South Africa a solid start and got past her fifty
Jess Jonassen made the first breakthrough by removing Lizelle Lee and went on to take Dane van Niekerk's wicket later.