Spinner Kuldeep Yadav snared four batters as India bowled out South Africa for a paltry 99.
The spin trio of Yadav (4/18), Washinton Sundar (2/15) and Shahbaz Ahmed (2/32) shared eight wickets among them on a track that offered turn.
Mohammed Siraj (2/17) also chipped with two wickets.
In response, India knocked off the required runs in 19.1 overs with Shubman Gill making 49 off 57 balls.
South Africa: 99 all out in 27.1 overs (Heinrich Klaasen 34; Kuldeep Yadav 4/18).
India: 105 for 3 in 19.1 overs (Shubman Gill 49, Shreyas Iyer 28 not out; Bjorn Fortuin 1/20).