India made one change from their win against the Netherlands with Deepak Hooda coming in for Axar Patel in the second match of a double-header at the Perth stadium.
India edged out Pakistan in their opening match and a third win would boost their hopes of sealing one of the two final-four places in Group 2.
South Africa, led by Temba Bavuma, are a point behind table-toppers India and Bangladesh after a washout against Zimbabwe and a thumping victory over Bangladesh.
The Proteas selected an extra pace bowler in Lungi Ngidi on a pacy and bouncy pitch, which earlier witnessed Pakistan restrict the Netherlands to 91-9 and win by six wickets.
Spinner Tabraiz Shamsi misses out for South Africa, who have never won a cricket World Cup.
India: Rohit Sharma (capt), KL Rahul, Virat Kohli, Suryakumar Yadav, Hardik Pandya, Dinesh Karthik, Deepak Hooda, Ravichandran Ashwin, Mohammad Shami, Bhuvneshwar Kumar, Arshdeep Singh
South Africa: Quinton de Kock, Temba Bavuma (capt), Rilee Rossouw, Aiden Markram, David Miller, Tristan Stubbs, Wayne Parnell, Keshav Maharaj, Kagiso Rabada, Anrich Nortje, Lungi Ngidi
Umpires: Langton Rusere (ZIM), Richard Kettleborough (ENG)
TV Umpire: Richard Illingworth (ENG)
Match Referee: David Boon (AUS)