Electing to take guard, Bangladesh scored 147/7 in their 20 overs thanks to a 80-run knock by Sabbir Rehman which included 10 boundaries and three sixes.
Shakib Al Hasan and Mahmudullah made 32 and 23 runs respectively for the team.
Dushmantha Chameera took three wickets while Angelo Mathews and Nuwan Kulasekara bagged a wicket each.
The Lankan side could only manage 124/8 on the board in their alotted 20 overs. Dinesh Chandimal made 37 runs for the team while Shehan Jayasuriya made 26 runs for the team.
Al-Amin Hossain picked three wickets while Shakib Al Hasan dismissed two batsmen.