India were 35-3 in pursuit of a record target of 287 at stumps on day four at Centurion.
Ishant Sharma took two wickets as the Proteas crawled to tea on 230-7 on day four at Centurion.
Mohammed Shami claimed three key wickets to reduce the Proteas to 173-5 at lunch on day four.
Morne Morkel has ruled out a draw at Centurion and says a lead of 250 might be enough for the Proteas.
The Proteas were 118 runs ahead and still had eight second-innings wickets in hand at stumps on day three at Centurion.
Virat Kohli scored 141 not out to reduce the first-innings deficit to 48 runs at lunch on day three at Centurion.
Proteas Test debutant Lungi Ngidi says bowling shorter spells helps him to bowl consistently at a high intensity.
The Proteas produced a combative all-round performance to reduce India to 183-5 at stumps on day two at Centurion.
India were 4-0 at lunch after bowling the Proteas out for 335 on day two at Centurion.
Aiden Markram fell short of a well-deserved century as South Africa went to tea at 182-2 on day one at Centurion.