England assert themselves and send out a warning to the other title contenders, while Bangladesh showed that they were no mere pushovers.
"And one of the strongest parts of reinforcing the way that we play, and the freedom in which we play with, is backing that up with selection".
294 Previous highest successful chase in the Champions Trophy, by Sri Lanka against England at The Oval.
Roy, so unequivocally backed by Morgan to open for the entire tournament despite his lack of runs, had to reflect on his fifth single-figure score in his last six ODI innings after paddling an attempted ramp-sweep just within the clutches of short fine-leg - where Mustafizur Rahman held a memorable leaping catch above his head. He along with skipper Mushfiqur Rahim (79) added 166 runs in 25.1 overs to hand a crucial advantage to the visitors.
Their twin exits in the 45th over stalled Bangladesh, which embarrassed England at the last two Cricket World Cups.
Hales led their partnership, scoring freely in front of the wicket.
Hales was the aggressor in the partnership, hitting 11 fours and couple of sixes before missing out on a well deserved hundred.
The duo made 159 in the second wicket to bring England back to the game, leaving Bangladesh to rue their failure to make the best of a bright start.
Root, whose right calf began cramping midway through his innings, finished the match with a pair of boundaries - Nos.
Root also suffered an injury scare when he damaged his calf early in his innings but he made light of the problem to post his highest one-day global score.
Root never went for the big hits, but played smart cricket to ensure that the chase never comes under pressure.
That England are the bookies favourites speaks volumes for their improvement since the 2015 World Cup.
"It's a lesson with the bat and ball. our bowlers to be disciplined and to our batsman that, sometimes, you have to sit in", Morgan told reporters after the match.
"Ben Stokes has had a little bowl today, and we will see how he pulls up tomorrow to see how much he will bowl - but I certainly see him bowling".
That was the cue for Tamim and the diminutive Mushfiqur to take charge.
Tamim started on a cautious note getting his first boundary off 21st ball that he faced.
That left England on 257-2 and needing just 49 to win from 43 deliveries.
Plunkett added Sabbir Rahman's wicket in the last over to finish with a team-best 4-59.
England's batting, in particular, has gone up several levels - of their 10 totals of 350 or more in the 50-over format, eight have come since their elimination in Australia and New Zealand two years ago.