"We talked on the bench about having a right-left combo, being able to attack one side all the time, so managed to sneak up the order and make the most of it," Buttler said in an on-ground interview after being named man-of-the-match.
"Fantastic wicket and some small boundaries, so glad to make the most of it."
Buttler and Morgan (103) guided their team to 418 for six, England's highest one-day score against West Indies and third highest against any opposition.
But if England thought victory was assured, they were given a fright by Chris Gayle, who bludgeoned 162 for West Indies and Buttler said the hosts' performance was a reminder of the challenges England face when they host the World Cup later this year.
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"It just goes to show, no matter who's favourites, on any given day there will be unbelievable games of cricket, and if Chris Gayle is in the opposition, you can lose those games," Buttler told Sky Sports.
"I've probably never seen anyone hit sixes as easy as he can. He's a legend of the game."
Gayle has said he would retire from one dayers after the World Cup, but on Wednesday the 39-year-old created some slight doubt about that decision.
"What's the matter with the body? I'm nearly 40," he told specialist cricket website Cricinfo.
"But could I un-retire? We'll see. We'll take it slowly."
(Reporting by Andrew Both in Cary, North Carolina; Editing by Greg Stutchbury)
