Last year's losing finalists were all but out of the game after being restricted to 128 for six, having lost their first three wickets inside five overs after Sangakkara won the toss at the Beausejour Stadium.
England then completed a comprehensive victory with four overs to spare as Kevin Pietersen, showing no sign of jet lag after flying back from London following the birth of his son, finished on 42 not out.
Only Angelo Mathews, with 58, made more than 16 and the collective failure of their top order cost Sri Lanka dear.
"In the first six overs if we'd got 40 runs with wickets in hand we could have accelerated through the middle but we lost three wickets early," Sangakkara, who himself only made 16, said.
"Angelo Mathews played very well but we didn't bat smartly today.
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Sri Lanka were particularly perplexed by the England seamers' use of the slow, looping bouncer.
"Everyone has those sorts of deliveries these days but it's how you use them that counts and I thought Engl