South Africa chase down 189 with eight balls to spare.
Series level 1-1 after skipper Duminy finishes match with two consecutive sixes.
J P Duminy and Heinrich Klassen hit superb half-centuries to steer South Africa to a six-wicket victory over India in the second Twenty20 International, in Centurion, on Wednesday night.
Chasing a challenging 188 for four, after putting India in to bat, the home side was home in 18.4 overs, thanks to a 30-ball 69, that included 3 fours and 7 sixes, by Klassen which put the Proteas on course for victory.
Fittingly, skipper Duminy got the winning runs, hammering two consecutive sixes to finish unbeaten on 64 off 40 balls, which included 4 fours and 3 sixes.
Farhaan Behardien was not out on 16 off 10 deliveries, including one six.
The unheralded Klaasen played a blinder of an innings while Duminy led from the front as India’s bowlers, especially leg-spinner spinner Yuzvendra Chahal, found it difficult to grip the ball following a constant drizzle that prevailed for most part of the South African innings.
The hosts made a modest start to their chase, with openers Reeza Hendricks (26) and Jon-Jon Smuts (2) sharing 24 runs for the opening wicket.
Left-arm pacer Jaydev Unadkat (2/42) broke the partnership when he induced a leading edge in the fourth over from Smuts which was gleefully accepted by Suresh Raina.
To make matters worse for the hosts, Hendricks departed off the final delivery off the next over, caught by Hardik Pandya at deep square leg off Shardul Thakur.
However, Klaasen and Duminy brought South Africa back into the match with a blazing 93-run stand for the third wicket which came off just 49 balls after they were down to 38 for 2 at one stage.
Klaasen used the crease to perfection and struck three boundaries and as many as seven sixes during his fiery knock in front of his home crowd.
Duminy played second fiddle and gave Klaasen the perfect support from the other end as the wicketkeeper-batsman went hammer and tongs.
After putting South Africa in sight of victory, Klaasen departed when he top-edged a Unadkat delivery straight to Dhoni behind the stumps in the 14th over.
Thereafter, Duminy took the onus on himself to guide South Africa home and with Behardien shared unconquered 48 runs for the fifth wicket to seal the series-levelling victory.
Earlier, Manish Pandey and Mahendra Singh Dhoni hit breezy half-centuries as India amassed 188 for four.
Pandey finished unbeaten on 79 off 48 balls, while veteran Dhoni scored 52 off 28 deliveries.
The duo shared 98 runs for the fifth wicket off just 9.2 overs to guide India to the commanding total.
Sent in to bat, India were dealt a severe blow off the first ball of the second over when Rohit Sharma was trapped plumb in front of the wicket by Junior Dala (2/28) for a duck.
Shikhar Dhawan (24 off 14), however, came to the party and clobbered Chris Morris for two fours and as many sixes in the third over to up the ante.
Suresh Raina (31 off 24) matched his partner stroke for stroke and hit right-arm pacer Dane Peterson for three boundaries in the next over to take India to 40 for one after four overs.
With his pacers going for runs, skipper J P Duminy brought himself on to the attack in the next over but was welcomed by Dhawan with an exquisite pull to the mid-wicket boundary.
Duminy, however, got his man off the next delivery, as Dhawan hit a full toss straight to Farhaan Behardien at mid-on.
India suffered a big blow in the next over as skipper Virat Kohli gloved a rising Dala delivery straight to Heinrich Klaasen behind the stumps.
Thereafter, Raina and Pandey added 45 runs off 31 balls for the fourth wicket to take India forward.
But the dangerous-looking partnership was broken by Andile Phehlukwayo in the 11th over when he had Raina leg before.
After Raina's dismissal, Pandey and Dhoni mixed caution with aggression to step up the scoring.
The duo took time to settle down but once they got their eyes set, they clobbered the South African bowlers.
While Pandey struck six boundaries and three sixes during his knock, Dhoni was not far behind his younger partner as he found the fence four times and over it thrice.