|Fourth one-day international, Pallekele|
|Sri Lanka 273-7 (50 overs): Shanaka 66, Dickwella 52, Moeen 2-55|
|England 132-2 (27 overs): Roy 45, Akila 2-27|
|England win by 18 runs (DLS method)|
England sealed the series against Sri Lanka with victory in another rain-affected one-day international.
The improved hosts posted 273-7 in their 50 overs, with Niroshan Dickwella and Dasun Shanaka both hitting fifties.
But England were ahead of the rate on 132-2 from 27 overs when play was suspended at 11:15 BST in Pallekele.
The game was called off at 12:10, giving England victory by 18 runs on the Duckworth-Lewis-Stern method and a 3-0 lead in the five-match series.
Joe Root and Eoin Morgan ended unbeaten on 32 and 31 respectively to help guide their side to a winning total after openers Jason Roy (45) and Alex Hales - who made 12 in place of the injured Jonny Bairstow - had been dismissed.
The final match of the series is in Colombo at 10:00 on Tuesday.
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England make it nine in a row
England have now won their past nine one-day series of two or more matches following a 2-1 defeat by India in January 2017. They lost the sole ODI against Scotland last year.
Since the group-stage exit at the last World Cup, Morgan's side have won 51 of 76 one-day internationals, losing 20, with one tie and four no results.
The weather and a limited Sri Lanka side have ensured this series has not offered the world number one ODI side many tests to their status as favourites to win the World Cup on home soil next year.
However, the tourists have perhaps answered whether they can adapt their batting to slower, turning wickets - something they failed to do in a heavy defeat by Pakistan in the Champions Trophy semi-finals last year.
This pitch in Pallekele was not as tough as that used deck in Cardiff, but Roy, Root and Morgan all easily found gaps in the field off Sri Lanka's spinners to keep accumulating runs before attacking the bad ball.
Only Akila Dananjaya offered a real threat with his mix of off-breaks and leg-breaks, drawing Hales out of his crease to be narrowly stumped and trapping Roy lbw after a successful review.
Improved Sri Lanka still lacking
Sri Lanka have not won a home one-day series since beating West Indies in 2015 and never looked like breaking that streak against a superior England outfit.
Dinesh Chandimal's side did post a total that could have proved challenging though, with Dickwella - who smashed 36 from 20 balls in the rain-shortened third ODI - adopting a more circumspect approach in overcast conditions.
The opener saw off the accurate Chris Woakes, attacked Olly Stone's loose deliveries and nudged the spinners around to reach fifty off 65 balls, only to fall shortly after as Moeen Ali got one to straighten from round the wicket and trap him lbw - the ball hitting his elbow in front of the stumps as he tried to sweep.
Dickwella also impressed at times behind the stumps, sharply whipping the bails off when Hales dragged his toe out and was unable to slide back in time, before he convinced Chandimal to review after Roy was initially given not out to Akila.
Sri Lanka's progress was briefly checked as Chandimal was bowled through the gate by Moeen after skipping down the pitch and Kusal Mendis was removed lbw by Adil Rashid, but they refused to crumble - Shanaka (66) and Thisara Perera (44) combining to bring their side up to a decent score.
Yet more mistakes cost them - Root was reprieved on 22 despite chipping a low full toss from Dhananjaya de Silva straight to fine leg, with square leg umpire Lyndon Hannibal spotting the hosts did not have the requisite five fielders in the circle and signalled a no-ball.
Had it been a legal delivery, a third wicket would have put England level with the DLS par score at the time and ensured a tougher ask to stay ahead of the rate.
Mixed day for World Cup outsiders
Aside from a relatively sloppy fielding display compared to their usual standards, the only other concern for England was the performances of two outside contenders for a World Cup place.
Hales came in for his first ODI since June after Bairstow twisted his ankle playing football in training on Friday, but dropped a catch on the boundary to concede a six and was out before his innings could really begin.
Stone was quick but wayward in conceding 50 runs from his seven overs, with Liam Plunkett back in the squad after getting married and pushing to reclaim his place.
Yet Tom Curran bowled well in taking 1-50 off nine overs, while mainstays Woakes, Moeen and Rashid - both spinners bowled 10 overs straight - were as assured as ever.
'A scrappy game' - match reaction
England captain Eoin Morgan: "It was a scrappy game. We could have been more disciplined in the areas we bowled. Credit to Sri Lanka. They fought back well and played our spinners well.
"The fact we have won the series doesn't mean we won't want to win the next game - but it may be an opportunity to look at other guys as well."
Sri Lanka captain Dinesh Chandimal: "We batted well and can take the positives from that. I think 274 was a winning total, weather permitting, but unfortunately it wasn't to be. Overall we played some outstanding cricket.
"That no-ball to Joe Root was our mistake. We could have won the game if it wasn't a no-ball, but we have to take that."
Former England captain Michael Vaughan on The Cricket Social: "This series has taught me that this England team is tough.
"There might be a stage at the World Cup like this. You don't win a World Cup without luck. I do fancy England will be lifting the trophy next year."