South Africa won the toss and decided to bowl in the second semi-final of the women's Twenty20 World Cup on Thursday against defending champions Australia after rain cleared in Sydney.
The winner will play India, who reached their first final after their clash against England was washed out in Sydney earlier in the day.
South Africa have never made the final before, and have never beaten top-ranked Australia in any format in the women's game.
"With rain around we want to know exactly what we need to do in a semi-final," skipper Dane van Niekerk said, on why she opted to bat.
"But having said that we are going up against the number one team in the world today."
Australia, who are targeting a fifth world title, go into the game without star all-rounder Ellyse Perry who has been ruled out of the tournament with a hamstring injury.
Spin bowling all-rounder Sophie Molineux takes her place.
"There might be some more rain coming so I was happy to let South Africa choose," said Australia skipper Meg Lanning. "The strip looks really good."
Australia: Beth Mooney, Alyssa Healy, Meg Lanning (capt), Ashleigh Gardner, Rachael Haynes, Jess Jonassen, Sophie Molineux, Nicola Carey, Delissa Kimmince, Georgia Wareham, Megan Schutt
South Africa: Lizelle Lee, Dane van Niekerk (capt), Sune Luus, Mignon du Preez, Laura Wolvaardt, Chloe Tryon, Nadine de Klerk, Trisha Chetty, Shabnim Ismail, Ayabonga Khaka, Nonkululeko Mlaba
Umpires: Kim Cotton (NZL), Nitin Menon (IND)
TV umpire: Langton Rusere (ZIM)
Match referee: Chris Broad (ENG)