Soumya Sarkar and Mosaddek Hossain starred in an excellent chase as Bangladesh won the tri-series final against the West Indies in Dublin.
Openers Shai Hope and Sunil Ambris both struck half-centuries as the Windies reached 154-1 from 24 overs before rain interrupted play.
That left Bangladesh with a tricky total of 210 to win from 24 overs on DLS method when play resumed, but they got over the line by five wickets and with seven balls to spare.
Bangladesh, ended the tri-nation tournament with four wins in as many games, beating Ireland once and the West Indies three times.
Soumya got his side off to a quick start with a 41-ball 66 at the top, while wicket-keeper Mushfiqur Rahim struck 36 before both were dismissed by Raymon Reifer, giving the left-arm seamer his first one-day international scalps.
But all-rounder Mosaddek Hossain powered Bangladesh to the finish line with an unbeaten 52.
Mahmudullah completed the job with a fine drive over the cover fielders.
The West Indies will be strengthened by the arrivals of Chris Gayle and Andre Russell ahead of the World Cup, while Bangladesh will be hoping that Shakib Al Hasan gets fit from a back strain that kept him out of the contest on Friday.