The majority of spectators at Malahide on Saturday had probably never heard of Sunil Ambris never mind seen him play before, but it was the St Vincent batsman's maiden century which ended Ireland's hopes of a first home win against a major Test nation.

Ambris, who is not in West Indies' World Cup squad, was playing only his fourth one-day international but he charged past his previous scores of 38 not out and 38 to hit 148 and render Ireland's fifth highest total in an ODI inadequate.

As Ireland's century-maker Andrew Balbirnie admitted afterwards: "It doesn't feel like that first innings happened. Having put 320+ on the board, it's a bitter pill to swallow."

With Balbirnie continuing his rich vein of form, Paul Stirling - dropped on 10 - posting his first half-century of the season and Kevin O'Brien and Mark Adair finishing the innings strongly, Ireland rightly believed they had posted a winning total.

After all, they had never lost having scored as many - and West Indies had never successfully chased more than 309. But the Ireland bowlers could not repeat their early heroics against England on this square eight days earlier as Ambris took the visitors within 80 runs of victory and Jonathan Carter and skipper Jason Holder found it so easy to maintain the momentum that West Indies had 13 balls to spare at the finish.

"We've blown hot and cold these last few games, we got it right with the bat this week, got it right with the ball last week and it's just a matter of combining both and putting in a performance that gets us over the line," added Balbirnie, whose flawless and fluent 135 was Ireland's sixth highest score in an ODI.

Only Ed Joyce has scored more in an ODI in Ireland and for much of this innings, Balbirnie looked so good that it was as if Ireland's greatest batsman had just changed his stance.

"Once you got used to the pace of the pitch, you got good value for your shots and it got easier but that's the art of batting," said the 28-year-old Dubliner.

"If you get through the first 20 balls of your innings you can really push on and fortunately I was able to do that but their guy was able to do that a bit better.

"I've felt good for the last two games, but found myself getting out weirdly - getting hit on the head and then run out or stumped, whatever it was (in the England match) - but I felt good in training and was moving well and to put on a big score as a batting group was great. It was great for Stirlo to get out there and score 70 and Kev to come in and do what he has been doing well for the last few months."

West Indies' record chase also booked their place in Friday's Tri-Series final and because of Ireland's vastly inferior run-rate their only hope of joining them is for a Windies victory against Bangladesh at Malahide today and Ireland to get a bonus-point win against the Tigers at Clontarf on Wednesday.

The fact that Bangladesh, with their full World Cup squad, defeated West Indies, missing seven of their 15 for England, last week underlines the likelihood of that scenario. Although Boyd Rankin took three of the wickets, he conceded more than eight runs an over and it was Stirling who was actually Ireland's best bowler.

The problem for captain William Porterfield, however, was because of their lack of early wickets there was only one left-hander batting in the first 39 overs. Stirling needed only four balls to get rid of Darren Bravo but when Carter finally arrived in the middle, Porterfield obviously considered it too risky to recall Stirling in the last 10 overs.

Instead, he had to watch the inexperienced Josh Little and Adair feel the force of Holder and Carter's bat but, then, Rankin also conceded a six in each of his last three overs as the Windies powered home.

Ireland have that must-win match against Bangladesh next and Porterfield is approaching must-score territory if his glorious 292-cap international career is not to be interrupted. His dismissal on Saturday - caught at slip off an attempted turn to leg - for three continued his poor run of form and the fact that he gave up his opening slot in an ODI for the first time in two years was not just to allow James McCollum to open but to give himself a chance of 'easier runs' in the middle order.

In the end, it cost two early wickets as McCollum - who does not open for Waringstown - was caught behind for five. The captain needs more than a win on Wednesday.