The game began with West Indies winning the toss and choosing to bowl first.
Samuel Badree stifled Sri Lanka with an exceptional spell (3 wickets in 4 overs) before Andre Fletcher scored an unbeaten 84 as the West Indies cruised to a seven-wicket win over the defending champions on Sunday.
West Indies restricted Sri Lanka to 122 for nine and finally met their target in 18.2 overs.
They now sit at the top of the table in Group I with two wins from as many matches.
Sri Lanka lost their half batsmen in 10 overs. Sri Lanka owed their score to Thisara Perera, who top scored for the defending champion with a 40-run knock off 29 balls. The left-hander also added 44 runs for the sixth wicket with skipper Angelo Mathews (20).
Mathews and Perera's partnership ended when the former was out in a bizarre manner. He tried to duck a slow full toss from Dwayne Bravo but the ball kissed the bat and flew towards Dinesh Ramdin, who took an easy catch.
Perera kept fighting hard and found a few boundaries towards the end before holing it up to Andre Russell off Dywane Bravo (2/21).
West Indies opener Johnson Charles (10) and Marlon Samuels (3) were victims of turning balls with Milinda Siriwardana (2/33) and Jeffrey Vandersay troubling the batsmen a lot.
Fletcher sent in place of Gayle, who was nursing an hamstring injury, punished the Srilankan bowlers by smashing six fours and five sixes in his knock that came off 64 balls.
His innings was a superb mix of caution and aggression considering the conditions. His monstrous sixes off Siriwardana at the start of the 15th over nearly pushed Sri Lanka out of the game and it was matter of time that West Indies completed the chase.
West Indies won the game by 7 wickets with 10 balls to spare.
