A record-breaking batting innings, spearheaded by Orla Prendergast's half-century, proved not quite enough for Ireland as West Indies captain Hayley Matthews guided her side home by six wickets in pursuit of 138.
Ireland opted to go with an unchanged line-up from the side that faced England and Pakistan. Laura Delany won the toss for a third game in a row and opted to bat first.
It proved to be a good decision as, despite the early loss of Amy Hunter, the runs were soon flowing. Gaby Lewis took a while to get going but after she lofted cover drive for four and went past 1,500 T20I runs she began to tick along nicely.
At the other end, Orla Prendergast continued her form from the previous game against Pakistan and brought up her half-century from 40 balls.
The young all-rounder earned herself a free hit after spotting the extra West Indies fielder outside the inner ring - she planted the ball over deep mid-wicket for six. Prendergast's knock was her third fifty in T20Is, but the first by an Ireland batter at the Women’s T20 World Cup, surpassing Cecelia Joyce’s 39 from 2014 as Ireland's new highest individual score in the competition.
West Indies eventually removed the 20-year-old for 61 off 47 balls, a leading edge ending the 90-run partnership between Prendergast and Lewis - a new record for any wicket at the Women's T20 World Cup for Ireland.
Lewis fell a few overs later and the wickets began to tumble.
The batters were dismissed in each of the 16th, 18th and 20th overs, as well as one in the 19th. Despite the procession, the tail managed to take the score past 129 to break yet another Ireland record - 137-9 becoming their highest-ever Irish batting total at the Women's T20 World Cup.
The West Indies' chase got off to a quiet start as the Irish bowlers kept things tight up top. The economical start paid off, pressure forcing a mix-up between Matthews and Rashada Williams leaving the latter run out at the end of the powerplay.
Despite Matthew's continued resilience as she passed the fifty mark, Delany trapped Shemaine Campbelle plumb in front to keep Ireland just on top. With the required rate within touching distance for the West Indies, Chinelle Henry provided ample support for her captain as they put on a stand worth 74 from 56 balls.
The equation was down to 18 runs needed from 14 balls when Leah Paul finally broke the partnership to reinvigorate Ireland. But Matthews remained immovable while new batter Shabika Gajnabi took no time at all to get her eye in, crashing nine runs from her first three balls.
With six runs needed from the last over, it would have required something special for Ireland to stop a likely defeat. Matthews sealed the win with a ball to spare by carving a drive over cover-point for her ninth boundary to finish unbeaten on 66 from 53 balls.
Ireland's final match will be played against India on Monday, 20 February in Gqeberha.