All-rounder Andre Russell smashed a match-winning half-century as West Indies claimed a nail-biting one-wicket victory over South Africa in the fourth ODI at St George's Park.
The hosts' David Miller had earlier struck a first ODI century as he caressed 11 fours and three sixes in an unbeaten 130 from 133 balls to take the Proteas to 262 for eight in their 50 overs.
Russell took West Indies past their victory target with nine balls and just a single wicket remaining, hitting five sixes in his unbeaten 64 from 40 balls.
He put on 27 for the final wicket with Sheldon Cottrell (one) as the tourists pulled a game back in the series to go into the fifth and final match in Pretoria on Wednesday trailing 3-1.
The victory is a rare high-point on a disappointing tour for the Caribbean side, but should give them some confidence going into next month's World Cup, albeit against a much-changed Proteas lineup.
South Africa 262-8 in 50 overs (Miller 130*, Holder 4-53)
West Indies 266-9 in 48.3 overs (Samuels 68, Behardien 2-21)