Captain Alyssa Healy's decision gifts pace bowler Megan Schutt the chance to make an early impression in her 200th international game.
Schutt is the sixth Australian to reach the 200-game milestone, joining  Ellyse Perry, Alyssa Healy, Alex Blackwell, Meg Lanning and Jess Jonassen.
The opening ODI follows a three-match Twenty20 series which Australia won 2-1 - the Australians suffered their first-ever loss to the South Africans in any format in game two.
"Having never beaten them before until the other day, (we were) always a bit intimidated by them," South Africa's captain Laura Wolvaardt said.
"But now we've finally broken that hoodoo and we have the win against them, it does us well in the future."
The three-game ODI series continues at North Sydney Oval on Wednesday and next Saturday.
Teams:
Australia: Alyssa Healy (capt), Ashleigh Gardner, Kim Garth, Alana King, Phoebe Litchfield, Tahlia McGrath, Beth Mooney, Ellyse Perry, Megan Schutt, Annabel Sutherland, Georgia Wareham.
South Africa: Laura Wolvaardt (capt), Anneke Bosch, Tazmin Brits, Nadine de Klerk, Sinalo Jafta, Marizanne Kapp, Ayabonga Khaka, Masabata Klaas, Sune Luus, Nonkululeko Mlaba, Chloe Tryon.
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