One-day international, Mirpur: India 284-8 (49 overs) beat Bangladesh 238-9 (49 overs) by 46 runs
Gambhir used his feet superbly against the Bangladesh spinners
Gautam Gambhir hit his second one-day century as India won their series in Bangladesh with a game to spare.
The left-handed opener made 101 off 113 balls, including 11 fours, as they totalled 284-8 from 49 overs in Dhaka.
The tourists then restricted Bangladesh to 238-9 in reply, with 18-year-old leg-spinner Piyush Chawla taking 3-38.
Mashrafe Mortaza hit four successive sixes off Dinesh Mongia in his 42 off 22 balls but it was not enough as India wrapped up a 46-run victory.
Both sides made one change with Bangladesh recalling pace bowler Mashrafe Mortaza and India giving Chawla his one-day debut in place of Shanthakumaran Sreesanth.
Gambhir and Virender Sehwag put on 43 from the first seven overs after Rahul Dravid won the toss before Sehwag (21) hit Syed Rasel to a diving Javed Omar at mid-off.
Mahendra Dhoni was promoted up the order after his match-winning 91 not out in the opening game of the best of three series and batted responsibly to help Gambhir add 87 for the second wicket.
Dhoni made 36 before edging to the keeper off Mohammad Rafique, who claimed his second success by taking a return catch to remove the dangerous Yuvraj Singh for 24.
But Gambhir continued to use his feet superbly to combat the spinners and his placement was equally good as he reached three figures off 111 balls, his first limited overs century since making 103 against Sri Lanka in 2005.
The youthful Chawla was overjoyed after taking his first wicket
A weary swipe across the line saw him bowled by Rasel and Bangladesh picked up four more wickets late on as India tried to accelerate, Rafique finishing with figures of 3-59.
The home side were soon in trouble at the start of their innings with Tamim Iqbal gesturing in frustration at partner Javed Omar after being sent back when he called for a quick single, only to be beaten by Chawla's throw and run out for seven.
Omar (11) and Saqibul Hasan fell to Zaheer Khan and Mohammad Ashraful (12) followed when he was deceived by Chawla's googly and edged an attempted cut into his stumps.
Aftab Ahmed hit a six and five fours in an aggressive 40 but was bowled when he was lured down the pitch by off-spinner Ramesh Powar and failed to make contact.
Habibul Bashar (43) and Mushfiqur Rahim (35) put on 59, but when Bashar was stumped off Chawla, his side were in the impossible position of having to score another 108 runs off just eight and half overs to win.
Mortaza gave local supporters something to cheer with his assault on Mongia, a tremendous effort considering he was suffering from cramp, but he holed out off Chawla at the start of the penultimate over.