England captain Eoin Morgan said in his eve-of-tournament news conference that Roy will "definitely play" in the Champions Trophy, that his opening partnership with fellow big hitter Alex Hales was a vital part of a team that has grown in stature in its ODI renaissance since the 2015 Cricket World Cup.
Earlier, riding on Tamim Iqbal's brilliant 128, Bangladesh posted a challenging 305/6. Then Root, who had 59, twisted on his right foot after playing a pull shot off Rubel Hossain.
He was not about to divert from his principles either as England prepare to begin their latest bid for a first one-day worldwide global trophy in their history.
Morgan cited Roy's role in helping England reach the final of last year's World Twenty20 in India - where they lost to the West Indies in Kolkata - as proof of how he could come good in a tournament.
Placed in Group A alongside New Zealand, Bangladesh and England, the reigning World Cup champions face the hard task of adjusting fast to the demands of the 50-over version of the game and to the conditions in England as they try to win the Trophy for a record third time. You can get on to the pitch and hit some sixes and fours!
Root deftly worked the ball off his pads and behind square on the off side and, despite being in obvious discomfort after suffering the injury on 61, completed a 10th ODI hundred.
"You will see us playing to the best of our capabilities".
Victory came at a price, though, for the bookies' title favourite.
The left-arm quick did bowl during training on Wednesday, but not at full tilt. Finally after getting bowled out, a burrowing umpire shows us out.
Both are world-class performers with the bat, but they go about their task in a very different manner.
But Tamim skied to Jos Buttler and Mushfiqur holed to long on from successive Plunkett deliveries to halt the Tigers' momentum.
Mushfiqur then punished Ball for dropping short by cutting him to the third man boundary. Their departures stalled Bangladesh just when it needed to be surging.
After winning two warm-up games against New Zealand and Bangladesh, the Indian team, who have retained several players from the victorious 2013 side, is high on confidence and will be looking to continue their form throughout the tournament.
You have a World Cup to crown the best 50-over team, the World T20 for the best T20 side, but the Champions Trophy is what exactly?
Bangladesh has the Australians on Monday.
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