Openers Shai Hope and Sunil Ambris each made fifties because the Windies reached 154-1 from 24 overs prior to rain intervened.
That left Bangladesh with a difficult overall of 210 to win from 24 overs on DLS means when play resumed, however they made brief paintings of the objective to win by means of 5 wickets with seven balls to spare.
Bangladesh, who open their Global Cup marketing campaign towards South Africa at The Oval on June 2, ended the sequence with 4 wins from as many finished suits, beating Eire as soon as and the West Indies 3 times.
Soumya were given his aspect off to a flier with a 41-ball 66 on the best of the order, whilst wicket-keeper Mushfiqur Rahim struck 36 prior to each have been disregarded by means of Raymon Reifer, giving the left-arm seamer his first one-day global scalps.
However all-rounder Mosaddek helped Bangladesh race to the end line with a glowing, unbeaten 52.
With 27 had to win from the remaining 3 overs, the 23-year-old clubbed Windies spinner Fabian Allen for 3 sixes and a 4 in 4 balls, attaining his 2d ODI half-century from handiest 23 deliveries.
Mahmudullah finished the task with a tremendous power over the duvet fielders.
The West Indies will likely be bolstered by means of the arrivals of Chris Gayle and Andre Russell forward of the Global Cup after Indian Premier League responsibility, whilst Bangladesh will hope that Shakib Al Hasan recovers from a again pressure that saved him out on Friday.
Bangladesh win by means of 5 wickets (DLS means)