West Indies 242 for 9 (Pooran 52, Walsh 46*, Pollard 40, Singh 3-48) beat Ireland 237 for 9 (Stirling 63, Joseph 4-32) by one wicket
Bridgetown: West Indies clinched a first home ODI series win since 2014 thanks to a one-wicket victory over Ireland.
Paul Stirling's 63 helped the Irish to 237-9 with Alzarri Joseph taking a second straight four-wicket haul.
Nicholas Pooran hit 52 while an unbeaten 46 from Hayden Walsh saw the Windies close in on the target.
In a dramatic final over Ireland wasted two run-out chances before Sheldon Cottrell won it with a six off the penultimate ball to make it 2-0.
Mark Adair was at fault for the run-out opportunities as the ball slipped from his grasp twice with Cottrell getting a double reprieve.
The number 11, who earlier had figures of 3-51, capitalised by smashing a maximum when the Barbados hosts required two from the last two balls from Adair.
Joseph impressed in the five-wicket win over the tourists in Tuesday's opener and the paceman was again in fine form at the Kensington Oval.
He took the key wicket of opener Stirling as the Irish, who again won the toss, let slip a promising position of 110-2 with Simi Singh adding 34.
West Indies were struggling on 76-4 before Pooran and big-hitting captain Kieron Pollard (40) put on a 74-run partnership.
Pollard provided a highlight by blasting two successive Gareth Delany deliveries onto the the roof of the the Worrell, Weekes and Walcott Stand.
He was dismissed by a superb caught and bowled by Barry McCarthy (2-28) two runs after Singh (3-48) bowled Pooran.
At 148-7 the Irish were favourites for victory but Walsh, along with contributions from Khary Pierre (18) and Joseph (16), shifted the momentum and Cottrell sealed a narrow win.
The sides will meet again in Grenada on Sunday in the final ODI before a three-game T20 series.