Chasing 266 to record its first ever series-win on South African soil, India were tottering at 137 for six in 31.3 overs when rain stopped play for the first time last night.
When play resumed after more than an hour`s break, India were set a revised target of 260 from 46 overs but only eight balls could be bowled and skies opened up again, leading to another forced break.
Play never resumed again and the umpires called off the match with South Africa emerging winners by 48 runs. At that stage India were 142 for six in 32.5 overs.
Both the sides will now travel to Centurion for the fifth and final match tomorrow.
Virat Kohli waged a losing battle all alone for India as batting colleagues surrendered abjectly before the South African attack.
The young Delhi batsman gradually got into the groove and then took the South African attack by the scruff off its neck but ran short of partners as wickets kept tumbling from the other end.
Kohli single handedly took the fight for India and played an entertaining knock which came off just 92 balls with seven fours and two sixes.
Left-arm pacer Lonwabo Tostsobe (2/25) rattled the Indian innings early on with his two wickets.
Earlier, it was J P Duminy`s defiant unbeaten knock of 71 and his crucial stands with lower order helped South Africa post a challenging 265 for seven after opting to bat at the St George`s Park here.
But it was India who took good control over the match by reducing South Africa to 118 for five at one stage, only to see Duminy spoil the visitor`s party with his never-say-die spirit.
India`s chase began on a shaky note with Rohit Sharma (1) failing yet again as an opener but that did not stop Parthiv Patel, who was playing his first match of the series, and Kohli from playing some attacking shots.
Twice Patel (11) sent ferocious Dale Steyn to the boundary ropes and Kohli took 10 runs from Tsotobe`s one over with two shots to the fence.
However, the slow nature of the track soon forced both the batsmen to slow down.
Tsotsobe jolted the Indian run chase as he first had Rohit (1) caught at backward point and then trapped Patel, who replaced Murali Vijay in the playing eleven to make things difficult for Mahendra Singh Dhoni and his men.
India had still not crossed the 50-run mark and 15th over was on when Yuvraj Singh hammered spinner Johan Botha for a six to give momentum to the innings but an unnecessary paddle sweep cut short his innings. .