Mohammad Naeem hit 64 off 50 deliveries but Bangladesh slipped to 153 all out in their must-win match of the Twenty20 World Cup against hosts Oman on Tuesday.
Fast bowlers Bilal Khan and Fayyaz Butt took three wickets each to peg back Bangladesh after The Tigers elected to bat first in the second match of the day in Muscat.
Naeem and Shakib Al Hasan, who hit 42 off 29 balls before being run out through a sharp direct throw by Aqib Ilyas, put on a key second-wicket stand of 80 after losing two early wickets.
Naeem, who replaced Soumya Sarkar from the side that suffered a shock loss to Scotland in Sunday's Group B opener, survived two dropped catches on 18 and 26 to go on and raise his third T20 half-century.
The Oman bowlers kept picking wickets and could have limited Bangladesh to many fewer with better catching as Kashyap Prajapati dropped two chances and Jatindar Singh spilled another.
Earlier in the day, Scotland beat Papua New Guinea in the first match to record their second successive win in Group B, leaving Bangladesh needing a win to stay in the tournament.