Harbhajan Singh struck with 15 minutes left on the final day to ensure India squared the series with South Africa at Eden Gardens.
The controversial off-spinner trapped Morne Morkel lbw late in the final session to seal a dramatic innings and 58-run victory and claim a personal five-wicket haul.
Not only does the victory level the series at 1-1, it also sees India retain their place at the top of the ICC rankings.
South Africa stalwart Hashim Amla (127 not out) was left stranded at the non-striker's end after batting for more than 20 overs with number 11 Morkel.
Resuming the day on 115-3, still 232 runs behind India's first-innings score, Amla was once again pivotal to the Proteas' hopes of playing out the final day and securing a series victory for his side.
With key pace bowler Zaheer Khan sitting out the final day through injury, the onus was on India's spin duo Harbhajan and Amit Mishra to step up on the wearing final day pitch.
The pair were thwarted for more than an hour in an extended morning session by Amla and Ashwell Prince (23), however a loose shot from the latter presented Harbhajan with his first scalp of the day.
Mishra got in on the act shortly after, AB De Villiers trapped plumb in front for just three as the tourists hobbled into the lunch interval still 183 runs behind, but crucially with only five wickets in hand.
India renewed their push for victory in the afternoon session and Harbhajan extended JP Duminy's barren run when the left-hander was beaten all ends up by a flatter googly which trapped him in front.
South Africa were still 175 runs behind at that stage and Amla - the last recognised batsman - was left waging a lone battle with the tail.
Dale Steyn (1) offered little resistance, however Wayne Parnell (22) renewed South African spirits when he combined with Amla for a gutsy eighth-wicket stand.
Amla had moved into the 90s with consecutive boundaries off Ishant Sharma (2-84) and duly brought up his ninth Test century and third of the series with another off Mishra, who had shared the second new ball.
Parnell, however, was dismissed in the fourth over after the tea interval, momentarily losing composure when chipping Ishant straight to Harbhajan at mid-on.
Paul Harris (4) wasted 24 deliveries before he too fell to Ishant to put India one wicket from glory.
Morkel then joined Amla and India were put under severe pressure as the pair batted without alarm for over 20 overs.
But, with time ticking down towards stumps, Harbhajan eventually trapped Morkel in front, sparking wild celebrations in the stands and on the pitch.
Harbhajan finished the day with 5-59, while Mishra ended with 3-78.
Amla was named man-of-the-match and man-of-the-series for his heroics. He finished the series with an average of 494 - the second highest, behind Wally Hammond, in the history of Test cricket.