Ireland started well at the Bir Shrestha Shaheed Flight Lieutenant Motiur Rahman Cricket Stadium and had 40 runs on the board by the time opener Paul Stirling was dismissed for 21.
The Tector brothers, Tim and Harry, extended Ireland’s score to 71 before the former was out for 32.
Lorcan Tucker and Harry Tector helped Ireland past 100, and the tourists were in a strong position on 105-2 when Tucker was caught off Tanzim Hasan Sakib.
Curtis Campher was dismissed in the 17th over with Ireland on 142, but late hitting from Tector, who finished unbeaten on 69, and George Dockrell helped them post 181.
Bangladesh would have looked for a strong response but Ireland’s bowlers tore through their top order.
Tanzid Hasan Tamim (two) was dismissed by Humphreys in the first over, while Litton Kumer Das (one) and Parvez Hossain Emon (one) both fell to Mark Adair, leaving the hosts 5-3 midway through the fourth over.
Saif Hassan was the next to fall on six as he was bowled by McCarthy leaving Bangladesh 18-4.
Wickets continued to tumble and Bangladesh fell well short of Ireland’s total, despite the best efforts of Tawhid Hridoy who finished unbeaten on 83.