Asked to bat first, South Africa rode on an unbeaten run-a-ball 99 by Wandile Makwetu to post 282/8 in their 50 overs.
Pacer Hermann Rolfes then clinched a four-wicket haul as the Proteas dismissed the West Indies for 206 runs in 45.3 overs.
South Africa have thus booked a spot in the next round with four points from two matches. Even if they lose their last group match against hosts and table toppers New Zealand, the Proteas will go through as one of the top two teams.
West Indies' hopes of defending their crown has gone up in smoke as they are out of contention after losing both the matches they have played so far.
The controversial dismissal of South Africa opener Jiveshan Pillay for obstructing the field was one of the biggest talking points of the game.
The incident took place during the 17th over of the South African innings when Pillay stopped the ball from going on to hit the stumps. He then immediately picked up the motionless ball and threw it to West Indies wicket-keeper and captain Emmanuel Stewart, who then appealed.
The on-field officials consulted the third umpire before Pillay was adjudged dismissed as per Law 37.4 of the MCC rules.
The South Africa opener was unlucky to miss out on what would have been a well deserved half-century as he scored a steady 47 runs off 51 balls with five boundaries and a couple of sixes.
Prior to his dismissal, Pillay had produced an opening stand of 56 runs alongwith Matthew Breetzke before the latter fell victim to a superb caught and bowled effort by West Indies pacer Jarion Hoyte.
Hoyte was in the thick of things in the very next over when he produced an accurate throw which hit the stumps to run out a diving Raynard van Tonder who was yet to open his account.
Pillay and Hermann Rolfes then went back in quick succession as the Proteas lost their top four batsmen with less 100 runs on the board.
Another run out sent Jason Niemand back to the pavilion as South Africa tottered at 112/5.
Makwetu and Kenan Smith tried to steady the boat with a 58-run stand. West Indies pacer Nyeem Young bowled Smith to break the partnership.
Gerald Coetzee and Jade de Klerk then produced a couple of quickfire knocks to help South Afirca stage a late comeback and post a strong total.
In reply, the West Indies never really managed to get going as they lost wickets at regular intervals.
A 97-run stand between Alick Athanaze and Kirstan Kallicharan was the only bright spot of the defending champions' innings as five of their batsmen failed to reach double figures.
Athanaze was their highest scorer with a 100-ball knock of 76 runs which contained six hits to the fence and a six.
Kallicharan scored 44 runs off 50 deliveries with five boundaries and a six.
Brief scores:
South Africa: 282/8 in 50 overs (Kallicharan Makwetu 99, Jiveshan Pillay 47) vs West Indies: 206 (Alick Athanze 76, Alick Kallicharan 44; Hermann Rolfes 4/33)
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
