Sri Lanka set a target of 236 runs against Bangladesh in the series deciding third ODI at Zahur Ahmed Chowdhury Stadium in Chattogram on Monday.
The visitors managed to score 235 runs losing all wickets in 50 overs.
Earlier, Sri Lanka won the toss and sent Bangladesh in to field.
Bangladesh made three changes for its quest to seal second successive ODI series victory against Sri Lanka.
Batter Anamul Haque, pacer Mustafizur Rahman and leg-spinner Rishad Hossain replaced Liton Das, Tanzim Hasan and Taijul Islam.
The visitors made one change with off-spinner Maheesh Theekshana returning to the side after pacer Dilshan Madushanka was ruled out of the series following a hamstring injury.
Line Ups:
Bangladesh: Soumya Sarkar, Anamul Haque, Najmul Hossain Shanto(c), Towhid Hridoy, Mushfiqur Rahim(w), Mahmudullah, Mehidy Hasan Miraz, Rishad Hossain, Taskin Ahmed, Shoriful Islam, Mustafizur Rahman
Sri Lanka: Pathum Nissanka, Avishka Fernando, Kusal Mendis(w/c), Sadeera Samarawickrama, Charith Asalanka, Janith Liyanage, Wanindu Hasaranga, Dunith Wellalage, Maheesh Theekshana, Pramod Madushan, Lahiru Kumara