West Indies' batsmen wilted to 215 all out from 44.1 overs as they chased the tourists' total of 280 for seven from 48 overs which was powered by Amla and de Villiers who both scored 102.
Amla registered his second career ODI century while de Villiers struck his third ODI ton on the trot as they put on 129 for the third wicket to lay the foundation for a big total.
Amla struck eight fours at the Sir Vivian Richards Cricket Grounds from 109 deliveries while de Villiers hit five fours and two sixes off 101 balls. All-rounder Dwayne Bravo bowled with control to finish with figures of three for 40 from 10 overs.
In the run chase, Chris Gayle top scored for the hosts with 45 from 39 balls including eight powerful fours while Kieron Pollard blasted 44 from 37 deliveries with five fours and a six. Their efforts were not adequate enough to threaten South Africa's total as lanky pacer Morne Morkel captured three for 40 from eight overs.He was supported by Dale Steyn and Ryan McLaren (both two for 37) and Johan Botha (two for 47). The second game in the five-match series will take place on Monday at the same venue.
SCORE BOARD
SOUTH AFRICA
Amla b Rampaul 102
Smith c Ramdin b Bravo 18
Kallis c Rampaul b Bravo 1
De Villiers c Sarwan b Taylor 102
Duminy b Rampaul 15
Miller (not out) 23
Botha b Bravo 3
McLaren c Gayle b Taylor 1
Steyn (not out) 2
Extras (LB-2, W-10, NB-1) 13
Total (for 7 wkts, 48 overs) 280
Fall of wickets: 1-53, 2-57, 3-186, 4-240, 5-259, 6-265, 7-268.
Bowling: Jerome Taylor 10-0-62-2, Ravi Rampaul 10-1-46-2, Darren Sammy 2-0-25-0, Dwayne Bravo 10-0-40-3, Nikita Miller 7-0-46-0, Chris Gayle 5-0-27-0, Kieron Pollard 3-0-19-0, Narsingh Deonarine 1-0-13-0.
WEST INDIES:
(Target revised to 282 off 48 overs)
Fletcher c Kallis b Steyn 3
Gayle c Botha b Morkel 45
Bravo c De Villiers b McLaren 15
Sarwan b Morkel 38
Deonarine c Kallis b Botha 26
Ramdin b Steyn 17
Pollard c McLaren b Morkel 44
Sammy c Kallis b McLaren 2
Miller (not out) 13
Taylor lbw Botha 0
Rampaul c Smith b Tsotsobe 3
Extras (LB-2, W-6, NB-1) 9
Total (all out, 44.1 overs) 215
Fall of wickets: 1-4, 2-44, 3-69, 4-130, 5-140, 6-192, 7-197, 8-203, 9-205.
Bowling: Dale Steyn 8-0-37-2, Lonwabo Tsotsobe 6.1-0-34-1, Ryan McLaren 9-1-37-2, Morne Morkel 8-1-40-3, Johan Botha 10-0-47-2, Jacques Kallis 3-0-18-0.
