Sehwag, who defied a hit on the knee, was in a murderous mood as he combined with young Virat Kohli (100 not out) to propel India to an imposing 370/4 before the visitors restricted the minnows 283/9 to avenge the shock defeat in the last edition.
Although the Bangladeshi batsmen made a valiant effort, the target proved much too stiff and ultimately lost their way as the asking rate kept mounting.
Tamim Iqbal (70) and skipper Shakib Al Hasan (55) were the notable contributors for Bangladesh.
For India Munaf Patel was the star performer with the ball with figures of 4/48 while Zaheer Khan also chipped in with two wickets for 41 runs.
Image: India's Virender Sehwag salutes the crowd as he leaves the field having scored157 in the opening cricket World Cup match against Bangladesh in Dhaka; Bangladesh, Saturday; Feb.19; 2011.