Banton and Brook lead England home in style.
Big hitting leaves Sri Lanka looking out of their depth.
England extended their hex over Sri Lanka to a 14th game, with the tourists looking as out of their depth as the balls that were repeatedly deposited into the River Taff as their opponents cantered to their target of 146 to win by six wickets, with 47 balls remaining.
More than a dozen years have passed since Sri Lanka, crowned world champions in the format a month earlier, beat England by nine runs at the Oval.
Only two Sri Lankans managed to the boundary, and none more than once. Tom Banton doubled their collective tally on his own on his way to his fifth and fastest half-century in T20s; Harry Brook managed three sixes, and he faced only eight balls.
The evening had started promisingly for Sri Lanka, put in to bat with the ball racing at the slightest invitation across an outfield slick from a brief pre-match shower, but they soon went from scoring at pace to unravelling with similar rapidity. Lahiru Udara, bumped up a spot to open, got the evening off to a strong start alongside Pathum Nissanka, and after five overs they stood at 55 without loss.
Udara, having scored 21 off 20, drove high to mid-on, where any fielder but the 6ft 5in Jamie Overton would have clawed at thin air but this one nonchalantly plucked it out of the sky.
With five to go the tourists found themselves on 115 for five, whereupon Charith Asalanka, the captain, and Wanindu Hasaranga plundered 18 to spoil the spinner’s figures.