On a day when many batsmen lost starts, Mominul was the brilliant exception who dug his heels in and kept the scoreboard ticking.
Bangladesh lost both their openers in the morning session after Shakib won the toss and elected to bat at the Shere Bangla National Stadium.
India dropped spinner Kuldeep Yadav for his eight-wicket haul in their comprehensive win in Chittagong, earning him the player of the match award.
Jaydev Unadkat was chosen instead and the left-arm pacer made his Test debut by dismissing Zakir Hasan for 15, playing his second Test 12 years after his debut.
Zakir, who scored a century on his Test debut in Chittagong, could have been dismissed for a golden duck but was dropped in the deep by Mohammed Siraj in his second over of the day.