Players came off twice before the game was called off with India at 142-6, giving the hosts a 48-run win.
Port Elizabeth: South Africa beat India by 48 runs on the Duckworth-Lewis method in a rain-affected fourth one-day international on Friday to send the five-match series to a deciding game.
Players came off twice for rain before the game was called off with India struggling at 142-6 in 32.5 overs, chasing South Africa's 265-7.
The winning total had been revised to 260 from 46 overs following the first rain delay but only eight more balls were possible before a second shower halted play for good.
Virat Kohli was 87 not out for India. Lonwabo Tsotsobe and Robin Peterson took two wickets each to put South Africa on top.
Earlier, JP Duminy's 71 not out helped South Africa recover to 265-7 against India in the crucial fourth one-day international at St. George's Park on Friday.
With India chasing an historic series-clinching victory, South Africa slumped to 118-5 before Duminy shared successive partnerships of 70 with Johan Botha, 54 with Robin Peterson and 23 with Dale Steyn at the end to rescue the innings.
Duminy hit two fours and a six in a near run-a-ball innings for the Proteas to post a competitive total and keep alive the home team's hopes in the five-match series.
India was on course for the win when South Africa lost four wickets for 12 runs — two to left-arm spinner Yuvraj Singh and two to run outs — before Duminy led the recovery. Yuvraj had 3-34, the best bowling return for India.
India has never won a one-day series vs. South Africa in South Africa. It leads this contest 2-1.
Hashim Amla inspired a positive start from South Africa after the home team opted to bat first in the day/night match in Port Elizabeth.
The opener hit a brisk, attacking 64 from 69 balls with eight fours before he fell to a needless run out — one of three in the Proteas innings.
Yuvraj had Morne van Wyk caught at slip by Virat Kohli and AB de Villiers stumped by Mahendra Singh Dhoni. Faf du Plessis was also run out for just 1 as India took control.
As it had done in its successive losses to fall behind in the series, South Africa endured a sudden batting collapse when Van Wyk's dismissal in the 20th over sparked the loss of four wickets for just 12 runs in 22 balls.
The recovery was led by Duminy, who shared back-to-back half-century partnerships with Botha (44) and Peterson (31) to lift the home team in sight of a challenging total for India's batsmen on a slow pitch which is traditionally difficult to score on under floodlights.
After South Africa slumped and appeared set for a third successive defeat, and its first-ever home series loss — in either tests or ODIs — to India, Botha hit three boundaries in the crucial sixth-wicket stand with Duminy.
Botha was stumped by Dhoni to give Yuvraj his third wicket but Peterson took over in support of Duminy as South Africa pushed toward 250.
Duminy reached a 12th one-day half-century, and second in successive games, when he guided a front-foot drive to the boundary through extra cover. His 50 came off 58 balls.
He launched the only six of the innings over wide long-on off Munaf Patel in the final over to set India 266 for an historic series win.