Lendl Simmons' 49 was the best that the West Indies could manage in reply, as Wiese's 5-23 helped to bowl it out for 126. Photo: Provided

Chris Gayle had led the West Indies to victory in the opening two matches of the three-match series, but with the hard-hitting batsman absent due to a back problem the Proteas comfortably avoided a series whitewash.

Van Wyk, who finished with 114 from 70 deliveries, shared in a century stand with Reeza Hendricks for the first wicket to set South Africa on its way to 195 for three in 20 overs.

Lendl Simmons' 49 was the best that the West Indies could manage in reply, as Wiese's 5-23 helped to bowl it out for 126.

The visitors made four changes to the side that broke a string of records in chasing down 232 at the Wanderers on Sunday, and its lack of sting in the bowling department showed as Van Wyk and Hendricks raced to 86 without loss in the eighth over.

"As we went on I started getting the pace of the wicket and felt that I was hitting the ball cleaner and cleaner," Van Wyk said.

The introduction of the experienced Dwayne Bravo and Kieron Pollard stemmed the flow of runs and ended the partnership on 111 when Hendricks was caught at deep midwicket, but Van Wyk found his touch again in the final four overs, hitting 39 runs in 16 deliveries.

Although the West Indies made a promising start to its reply, with Simmons scoring 43 of the 57 runs made in the powerplay, three wickets in 16 balls left the middle order with too much to do.

Wiese finished the game off as a contest when he took two wickets in his final over to become just the second South African to grab five wickets in a T20 international, before Marchant de Lange knocked over the tail to give the hosts a handsome victory.

"I think we owed this to ourselves because we played some outstanding cricket (in the first two games), but Chris Gayle was just too good," South Africa captain Justin Ontong said.