South Africa took a 2-1 lead in the five-match T20 series against West Indies, winning the third game by one run in Grenada on Tuesday.
Chasing 168, West Indies lost wickets at regular intervals and needed 15 off the last over with Fabian Allan and Dwayne Bravo at the crease.
Kagiso Rabada bowled a wide, leaked a four off the second delivery and was hit for a six off the last ball, but crucially bowled three dots that swung the game in the tourists favour.
Nicholas Pooran and Evin Lewis made 27 apiece, and Andre Russell struck three sixes in 25, while Andrich Nortje and Tabraiz Shamsi took two wickets each.
Earlier, left-arm seamer Obed McCoy took career-best figures of 4-22 and veteran Bravo bagged 3-25 as South Africa were held to 167-8. McCoy and Bravo combined for 23 dot balls in their combined four overs.
The in-form Quinton de Kock stroked 72 off 51 balls and Rassie van der Dussen made 32 off 24.
Match four in the five-match series is on Thursday, starting at 14:00h at the same venue.
