Du Plessis returned to lead the Proteas after being forced to sit out of the previous match due to a one-game suspension for slow over-rates.
India retained the same side that beat Australia in their last league match, keeping opener Shikhar Dhawan and seamer Mohammed Shami on the bench. The winner will meet Sri Lanka in Sunday's final. Sri Lanka knocked out defending champions West Indies in the first semi-final on Thursday.
India: Mahendra Singh Dhoni (capt), Rohit Sharma, Ajinkya Rahane, Virat Kohli, Yuvraj Singh, Suresh Raina, Ravindra Jadeja, Ravichandran Ashwin, Amit Mishra, Bhuvneshwar Kumar, Mohit Sharma.
South Africa: Faf du Plessis (capt), Hashim Amla, Quinton de Kock, AB de Villiers, JP Duminy, David Miller, Albie Morkel, Wayne Parnell, Dale Steyn, Beuran Hendricks, Imran Tahir.
Umpires: Kumar Dharmasena (SRI) and Ian Gould (ENG)
TV umpire: Bruce Oxenford (AUS)
Match referee: Ranjan Madugalle (SRI)