Sri Lanka won the toss and batted first on a beautiful day in Southampton, but struggled along as they were bowled out for 140 in their 20 overs. England were excellent in the field with debutant Liam Dawson the pick of the bowlers taking 3-27 from his four overs.
In reply, England were never really troubled as Jos Buttler, who finished 73 not out, and Eoin Morgan, who finished 47 not out, saw the team home with an unbeaten 114 run partnership.
The win meant that Sri Lanka didn't win a single game while on tour, while England showed once again how good they can be in the shortest form of the game.
Sri Lanka won the toss and chose to bat first
At a sun-drenched Ageas Bowl, Sri Lanka captain Angelo Matthews won the toss and chose to bat first on what looked like a great pitch to bat on.
Sri Lanka's innings didn't start too well after losing the early wicket of Kusal Perera for 13 of the bowling of Liam Plunkett but Danushka Gunathilaka and Kusal Mendis pushed the score along to 51-1 after the powerplay.
Dawson takes three wickets on debut
The pair were going along well until Dawson, on debut, got his first wicket when Gunathilaka was out for 26 trying to go for a big shot of the spinner. Dawson didn't have to wait long for his second and third wicket either as he got Mendis caught and bowled for 21 and then he bowled Matthews for 11 to leave Sri Lanka tottering at 81 for four.
Sri Lanka didn't help themselves either though as they lost another wicket straight after when Dasun Shanaka was run out by Jason Roy for one. The wicket of Shanaka brought Ramith Rambukwella to the crease on debut.
Rambukwella came out firing and played some big shots but was then run out when James Vince hit the stumps when he was on 19 to leave Sri Lanka on 106 for six in the 15th over.
Plunkett and Jordan restrict Sri Lanka to 140
Plunkett got in the action again soon after removing the dangerous Seekkuge Prasanna for one as the batsmen edged behind going for a big shot.
Despite some big hits from Dinesh Chandimal he fell for 23 of the bowling of Chris Jordan, to give England their eighth wicket, as he tried to get some late runs.
Sri Lanka lost their final two wickets as Jordan removed Farveez Maharoof for 10 and Nuwan Pradeep for a duck. Sri Lanka, therefore, were bowled out 140 from their 20 overs.
In reply, England got off to a bad start when Roy was bowled by Matthews for a duck. Vince came in at number three and he with Buttler started to build a partnership together.
The partnership had reached 30 before Matthews got his second wicket of the innings. Vince was the man out for 16 when he was stumped by Chandimal. It meant that after the powerplay England reached 41 for two.
Buttler and Morgan put on a century stand to see England home by eight wickets
Buttler though was still at the crease for England and along with captain Morgan the pair upped the run rate. The pair saw England home with 15 balls remaining with a brilliant unbeaten 114 run partnership with Buttler finishing the innings 73 not out and Morgan finishing 47 not out.