Bangladesh speedster Mustafizur Rahman has already bagged four wickets as Ireland are seven wickets down with only 136 on board.
Winning the toss, Tigers skipper Mashrafe Mortaza opted to bowl first and his bowlers vindicated his decision.
The first over, bowled by Rubel Hossain, was a maiden while Mustafizur Rahman removed Paul Stirling in the second over, which was a wicket maiden.
Mosaddek Hossain and Shakib Al Hasan also soon joined the party, as did Sunzamul Islam, who struck in the very first over on his ODI debut.
Ed Joyce has made 46 while Niall O'Brien added 30 to give the Irish scorecard a decent look.