Ireland 125 for 3 (Stirling 77) beat Bangladesh 124 (S Hossain 51, Adair 3-25, Humphreys 2-10) by seven wickets
Chittagong: Ireland defeated Bangladesh by seven wickets in the third and final T20 encounter after losing their opening five tour matches against the Tigers.
It was also Ireland's first win on Bangladesh soil as they avoided a T20 whitewash in Chittagong.
Matthew Humphreys had a T20 debut to remember, taking two wickets in his first three balls as Bangladesh were dismissed for 124.
Paul Stirling hit a quick-fire 77 as Ireland eased to 125-3 in 14 overs.
Ireland lost the ODI series 3-0 and were trailing 2-0 in the T20s going into Friday's final game at the Zahur Ahmed Chowdhury Stadium.
The hosts won the toss and batted first but they were quickly in trouble and slipped to 41-5 before Shamim Hossain made a valuable 51.
Humphreys, a 20-year-old spinner from Belfast, struck with his first ball by dismissing fellow T20 debutant Rishad Hossain and then accounted for Taskin Ahmed two balls later as he was caught at deep midwicket.
Mark Adair took 3-25 as Bangladesh were bowled out with four balls to spare and captain Stirling made it a comfortable chase for Ireland with his 77 from just 41 balls.
The big-hitting opener smashed four sixes and 10 fours while Curtis Campher added an unbeaten 16 as Ireland won with six overs remaining.
The sides will meet again in a Test match starting on Tuesday in Dhaka.