Off-spinner Simon Harmer bowled South Africa to a first Test win in India in 15 years after home skipper Shubman Gill was hospitalised with neck spams and unable to bat as his side crumbled chasing 124 for victory on day three in Kolkata.
Harmer followed his first-innings 4-30 with 4-21 during a dramatic conclusion to a low-scoring series opener, with India 93 all out and losing by 30 runs after a brief boundary-laden cameo from Axar Patel (26 off 17 balls) had threatened a heist from 77-7.
Axar pumped Harmer's fellow spinner Keshav Maharaj for two sixes and a four across the first four balls of the 35th over, only to then hole out attempting another big hit - South Africa captain Temba Bavuma taking a superb catch on the run - before Maharaj dismissed Mohammed Siraj next ball to secure victory.
The Proteas had lost seven and drawn one of their previous eight Tests in India since winning by an innings in Nagpur in 2010.
South Africa only needed nine wickets to take a 1-0 lead in this two-match series with Gill taking no further part in the game having retired hurt just three balls into his innings on day two shortly after sweeping Harmer to the boundary.
Rishabh Pant led India in the Proteas' second innings, in which the tourists rallied from 91-7 to 153 all out in a bowler-dominated contest, thanks to Bavuma (55no) - who scored the only half-century in the match for either side - and Corbin Bosch (25).
South Africa had been rolled for 159 in their first innings before India countered with just 189.
Bavuma went on to celebrate his 10th win in 11 Tests as captain as Harmer, Marco Jansen (2-15) and Maharaj (2-37) ripped through the home side at Eden Gardens on Sunday.
India slumped to 1-2 and 38-4 as seamer Jansen nicked off openers Yashashi Jaiswal (0) and KL Rahul (1) and Harmer dismissed Pant (2) and Dhruv Jurel (13).
Harmer then struck again, pinning Ravindra Jadeja (18) lbw after a stand of 26 with Washington Sundar (31) before catching Washington off Aiden Markram (1-5) at first slip and then trapping Kuldeep Yadav (1) lbw.
Axar's dashing knock may have given the away side a few jitters but Maharaj had the final say, with South Africa now eyeing just a second series win in India in the Test format and a first since a 2-0 victory in 2000 when they triumphed in Mumbai and Bengaluru.
The two-Test series, which concludes in Guwahati from November 22-26, is followed by a three-match one-day international series and then five T20 internationals.
