Kagiso Rabada derailed India in the second session with four wickets as South Africa reduced the visitors to 176 for seven at tea on the opening day of the first Test on Tuesday.
Rabada (5/41) picked up the wickets of Shreyas Iyer (31), Virat Kohli (38), Ravichandran Ashwin (8) and Shardul Thakur (24) in the post-lunch period that witnessed 50 overs being completed.
KL Rahul (39 not out) and Thakur shared 43 runs for the seventh wicket.
Earlier, India had reached 91 for three against South Africa at lunch.
Invited to bat, India were in a spot of bother at 24 for three Kohli and Iyer rode on luck to stabilise the visitors' innings with unbeaten 67 runs for the fourth wicket but could add just one after the break as Rabada came to the party.
Left-arm pacer Nandre Burger (2/39), who made his Test debut, also looked dangerous.
The toss was delayed due to wet patches on the outfield.
India handed Test debut to pacer Prasidh Krishna while all-rounder Ravindra Jadeja was unavailable for the series-opener due to back spasm.
India are aiming for their maiden Test series win in South Africa.
Maiden five-wicket haul for Kagiso Rabada against India. Rabada (178*) goes past Allan Donald's tally of 177 wickets in South Africa in six fewer Tests.
India reached 91 for three against South Africa at lunch on the first day of the opening Test of the two-match series on Tuesday.
Invited to bat, India were in a spot of bother at 24 for three before Virat Kohli (33 not out) and Shreyas Iyer (31 not out) rode on luck to stabilise the visitors' innings with unbeaten 67 runs for the fourth wicket.
Left-arm pacer Nandre Burger (2/23), who made his Test debut, looked dangerous while Kagiso Rabada (1/15) picked up the other wicket as South Africa managed 26 overs in the first session.
Earlier, the toss was delayed due to wet patches on the outfield.
India handed Test debut to pacer Prasidh Krishna while all-rounder Ravindra Jadeja was unavailable for the series-opener due to back spasm.
India are aiming for their maiden Test series win in South Africa.
I was not too sure (whether to bat or bowl first). We are quite aware of the conditions, we have been here a few times. We need to put runs on the board and the bowlers will do the job for us. We do understand the challenge of batting first with the overhead conditions and the grass, but the guys are up for the challenge. Everytime we come here, we come with high hopes. We've come close on the last two tours. We are pretty confident with our squad and the make-up of our squad. We are playing with four seamers and a spinner. Ashwin is playing in place of Jadeja. Jaddu had a bit of a back spasm, so Ashwin comes in and he is a quality spinner to have. Prasidh is making his debut, along with the other pacers Shardul, Siraj and Bumrah.