The Barbados captain Joshua Drakes dug his side out of a precarious position brought on by a spectacular batting collapse, on the hunt for a small target after Windwards were bowled out for 111 at the Demerara Cricket Club.
Chasing 112 to win Barbados lost early wickets as front-line batsmen struggled to negotiate a fiery opening spell from Sherman Lewis.
Lewis rocked the top order, grabbing three of the first four wickets to fall in the first seven balls and leaving the Bajans reeling on four for no run.
Windwards kept the pressure on Barbados as wickets fell regularly but Drakes batted responsibly to push Barbados closer to their target by compiling an unbeaten knock of 43.
He received little support except from Shamar Springer 14 and Chad Williams 10, the only two other batsmen to reach double figures.
Lewis finished with impressive figures of four wickets for 24 runs, including three maidens from nine overs.
Earlier, Windward Islands captain Roland Cato hit a top score of 23 before he was caught at long on attempting to rescue a struggling innings.
Tonis Simon chipped in with 19; Kershaskie Jno Lewis 14, and Anson Latchman hit Neil Persaud for two consecutive sixes then lost his middle stump.
Persaud, Williams and Matthew Jones picked up two wickets each for the winners.
Over at Bourda, half- centuries from Askay Homraj and Keemo Paul lifted Guyana to 229 for 9 against ICC, who were bowled out for 180, whilst giving chase.
Homraj top scored with 69, Paul scored 51, while Shimron Hetmyer added 21 to give the Guyanese a competitive total with ICC bowlers Keifer Phil, Arsh Buch and Nikhil Dutta capturing two wickets each.
ICC’s chase to reach a target of 220 ran out of steam early despite an impressive half-century from Onias Bascombe.
Bascombe hit the top score of 53, as ICC crumbled for 180 in 43.5 overs with contributions of 29 and 26 from Dutta and Farhan Malik, respectively.
Sharaz Ramcharran and Steven grabbed three wickets each.
The match between Leeward Islands and Jamaica at Wales Recreation Ground was abandoned without a ball bowled due to a wet outfield caused by overnight rain.