Despite having already won the series, England wanted to put on a show in the final game in Amstelveen, a day before the Test side play New Zealand at Headingley.
England achieved just that, Roy reaching third figures towards the end of the innings alongside a swashbuckling Jos Buttler as the tourists prevailed with 119 balls to spare.
However, the home side went from 203-4 to 244 all out with four deliveries left, David Willey the pick of the England bowlers with figures of 4-36.
England were left with a target which was several levels within their ability, and it came as little surprise when Roy and Phil Salt went on the offensive.
Despite that double blow, England were well inside the run-rate, even though that did not prevent Roy and Buttler from producing two explosive innings.
Buttler ended unbeaten with a strike-rate of 134.37, a knock of 86 featuring seven four and five maximums, but it was Roy who stole the headlines in the closing stages.
The opener was slightly more reserved, his 101 coming off 86 balls, and although he failed to post a six, 15 boundaries helped him to another three-figure score. body check tags ::