Jacques Kallis scored a century to guide South Africa to an unassailable 3-0 series lead over West Indies.
Kallis made an unbeaten 121 as the Proteas chased down the tourists' 252-7 with eight balls to spare and seven wickets in hand.
Having won the opening two matches, South Africa lead the series 3-0 with two more games left to play.
Fittingly it was Kallis who hit the winning runs, driving Jerome Taylor for four to complete his 133-ball innings with 12 fours and one six.
The hosts lost Herschelle Gibbs early in their reply when the opener was caught by Taylor off Daren Powell for 15.
However, Graeme Smith contributed 56 of a partnership of 82 with Kallis before falling to Marlon Samuels.
The departure of the Proteas skipper briefly slowed the run rate, but AB de Villiers made a brisk 18 off deliveries before becoming the third wicket to fall.
That brought JP Duminy to the crease with the score at 168-3 and he helped Kallis steer South Africa to victory with an unbeaten 35.
West Indies got off to a slow start with the partnership between Brenton Parchment and Sewnarine Chattergoon struggling to get going before the former perished to the bowling of Shaun Pollock for just five.
The inexperienced opener was clearly feeling the pressure of a slow start and after attempting to speed proceedings up, he could only sky his ambitious shot to Charl Langeveldt.
Despite this set-back with the score on only 27 Chattergoon swiftly passed his 50 as he and Patrick Browne put on an impressive stand of 72.
Chattergoon's bright innings of 52 was ended after he misjudged the flight of a Botha delivery, but there are promising signs as West Indies appear to have unveiled a potential gem at the top of the order.
Browne too gave Caribbean supporters cause for hope as he accumulated a well-crafted 35 which included two powerful sixes.
He too was deceived in an impressive Botha spell as he was eventually adjudged LBW with the score 110-3.
This dismissal brought together arguably the most temperamental pairing in the modern game - Runako Morton and Samuels.
Both on their day have the ability to cause the most destructive of damage, however these days have been all too few and far between in recent times.
Today, however was to be Samuels' day and he quickly got into his stride taking a liking to Langeveldt and Dale Steyn in particular.
It could all have been so different if Mark Boucher had clung onto a routine catch off the bowling of Pollock with Samuels only on 19.
Samuels made the Proteas pay and despite losing partners Morton (13) after being clean bowled by Kallis and Bravo (7) who was run-out, the powerful Jamaican weighed in with brutal hitting both sides of the wicket.
He and Sammy took the score up to 197-5 with seven overs remaining before Sammy was superbly caught by Smith at deep-midwicket off Langeveldt's bowling.