West Indies chased down 139 in 11 overs after Pollard and Bravo derailed the visitors with three wickets each.
Rain wreaked havoc as the second Twenty20 international between West Indies and Ireland was washed out in Basseterre on Saturday.
Tourists secure dramatic four-run win in opening T20I in Grenada on Wednesday.
Evin Lewis smashed a dazzling century as West Indies defeated Ireland by five wickets on Sunday to complete a 3-0 sweep of the one-day international series.
West Indies clinch last over thriller; lead 2-0 in three match series.
Evin Lewis remains unbeaten on 99, Alzarri Joseph takes four as Windies win by 5 wickets.