Roy ton powers England to victory in 2nd Bangladesh ODI
The victory, giving holders England valuable practice on spinning, low-bounce South Asian pitches before the 50-over World Cup in India later this year, meant that the visitors took the series 2-0 with one match still to play.
England dismissed Bangladesh for 194 runs in 44.4 overs, thanks to Curran's 4-29 and Adil Rashid's 4-45 after Roy struck 132 off 124 balls to guide the side to 326-7, the highest ODI score by a side in Dhaka in over five years.
The win also made England the first side to win an ODI series in Bangladesh in over six years, with the side also winning a series here last time in 2016.
Curran, replacing Chris Woakes, took three wickets in five balls in the opening two overs, including two in two balls in the first over to leave Bangladesh reeling at 9-3.
The hosts could never recover from the damage despite veteran all-rounder Shakib Al Hasan making 58 runs.
Shakib and skipper Tamim Iqbal shared 79 runs for the fourth wicket before Moeen Ali removed Tamim for 35 to end their resistance. Shakib was caught by Curran at extra cover off Rashid.
Bangladesh, who were playing their 100th ODI at Mirpur, earlier elected to bowl first and kept the tourists in check at the start.
Top-order batsmen Phil Salt (7), James Vince (5) and first-match centurion Dawid Malan (11) all fell cheaply. But Roy and skipper Buttler gave England lift-off with their fourth-wicket stand of 109.
Roy departed when Shakib had him out leg before.
Buttler then took over the charge until he was dismissed by Mehidy for 76 off 64 balls.
Moeen added a late blitz of 42 runs from 35 balls for reigning one-day and T20 world champions England.
Curran, one of the two changes in England squad from three-wicket win in Wednesday's opening match win, played his part with an unbeaten 33 off 19 balls.
Taskin Ahmed was the pick of the Bangladesh bowlers with 3-66.
Buttler paid tribute to Roy and called it a "fantastic" series win ahead of the final game on Monday in Chittagong.
"Bangladesh are a formidable team at home so we're delighted to get the win. (We) spoke about areas to improve from the last match and we really did that," cricket website Cricinfo quoted the England captain as saying.
"We'll assess the conditions and play accordingly, there's lots of guys putting their hands up and putting up performances, which is fantastic," he said.
Tamim said he was disappointed by the way Bangladesh bowled at the start while ruing a missed run-out.
"Roy and Buttler batted exceptionally well. When you lose, you can point fingers. I'm not going to do that. We didn't do well as a team, and that's why we lost," he said, according to Cricinfo.
