Sri Lanka 300 for 9 (Sangakkara 112, Dilshan 71, Gurney 4-55) beat England 293 for 8 (Buttler 121, Bopara 51, Malinga 3-52) by seven runs
Live scorecard and ball-by-ball details
Jos Buttler produced arguably England's greatest one-day innings - his first ODI hundred, the fastest for the country and the fastest at Lord's - but Sri Lanka clung on to level the series in a contest that became gripping during the latter stages of the chase.
Buttler's 61-ball century, eclipsing the 69-ball record of Kevin Pietersen at East London, brought England's requirement down to 12 off the final over but Lasith Malinga held his nerve as Chris Jordan holed out and Buttler was run out for 121 off 74 with two balls of the innings remaining.
He had come to the crease to join Ravi Bopara with England listing on 111 for 5 in the 29th over with the innings having included just four boundaries. They proceeded to add 133 in 16.2 overs to bring the equation down to 62 required off the last six when Bopara top edged a sweep off Ajantha Mendis.
But Buttler responded by taking 20 off the next over - bowled by Nuwan Kulasekara - including two skimming sixes over extra cover. Jordan dug out singles and twos where he could, scampering manically between the wickets, although it was basically down to Buttler who reached his hundred with a brace off Mendis. The force was with England but a single to Buttler off the first ball of the final over ate up a priceless delivery, especially when no runs were scored as Jordan was dismissed next ball at long-on.
It was a breathless finish to a match that was seemingly dribbing to a rather soporific conclusion. England needed to achieve their highest chase on home soil to seal the series after Sri Lanka posted 300 for 9 but for more than half the chase there was barely a whimper. They lurched to 10 for 2 against a supreme new-ball spell by Malinga and could never find the impetus to mount a challenge. At one point they went 130 deliveries without hitting a boundary before Buttler began his mission with a reverse sweep in the 31st over.
It was a performance that added fuel to well-worn arguments that England do not possess the required top-order power when a large score - and 300 is no longer the gargantuan total it was - is either there to be chased down or needed to be set. At one point Alastair Cook could be seen with head in hands on the balcony. He perked up during Buttler's onslaught, but his overriding emotion is likely to be one of frustration.
Sri Lanka would have struggled to accept this match slipping away although some of their bowling and fielding slipped under pressure. But they ultimately claimed victory and for much of the game it was another display of their resilience. Conditions were markedly different from Old Trafford yet it was still another striking turnaround having been bowled out for 67 three days ago led by Kumar Sangakkara's first hundred at Lord's.
Sangakkara and Tillakaratne Dilshan added 172 for the second wicket - Sri Lanka's third best stand for that wicket in ODIs - to form the backbone of the total. Although England fought back in the final 10 overs, a final-ball boundary by Mendis enabled Sri Lanka to cross the psychological 300 marker: England had only ever chased down more than 300 twice in their ODI history.
Sangakkara's innings will not get him a spot on the honours board - that is reserved for Test hundreds - but it did tick off one of the missing milestones in an illustrious career.
His previous best at Lord's in any format was 65 and he needed 13 balls to get off the mark but then progressed silkily to his hundred off 95 deliveries. The first of his 14 boundaries, a hook against Chris Jordan, did not come until his 27th ball but it was the three in a row he took off Joe Root that really launched his innings. When he was stumped off James Tredwell in the 43rd over he left to a standing ovation.
Sangakkara worked hard to find his timing before he clicked into gear with three consecutive boundaries off Root; twice using his feet to loft down the ground and then a peachy cover drive. Beautiful footwork also helped him beat mid-on off Tredwell and he latched on to loose deliveries from Ravi Bopara, who strayed on both sides of the wicket. The 10 overs combined of Bopara and Root cost 76 runs.
Sangakkara and Dilshan joined forces after Kusal Perera, brought in as Sri Lanka shuffled their order, edged a wild mow to slip. Dilshan scratched around, reaching 13 off 29 deliveries, before scooping James Anderson and following that with another boundary to fine leg.
Dilshan brought up his half-century the ball after Sangakkara but it always more of a battle for him. His last 21 runs soaked up 37 deliveries and he was also discomforted after a collision with Root in the bowler's follow through.
He fell in the first over of the batting Powerplay, attempting to scoop a full delivery from Anderson which took leg stump, and England regained a semblance of control. Mahela Jayawardene has been short of runs in this series and it was a scratchy innings from him. The final 10 overs brought 83 runs, fewer than Sri Lanka would have wanted.
Malinga produced a wicked four-over spell, trapping Cook lbw with one that swung back in and was overturned by the DRS and then finding Ian Bell's edge to slip. He did not concede a run until his 18th delivery and even then it was a squirted edge to third man.
Root and Gary Ballance tried to rebuild but it was painful progress. After the first 10 overs England were 34 for 2 and there was precious little lifting of the run rate. Ballance struggled against the spin of the recalled Ajantha Mendis and Sachithra Senanayake before edging a reverse sweep which summed up the innings which used 69 deliveries. Root had only faced one ball fewer when he top edged to fine leg.
England put great stock in the ability of their middle order but the asking rate was approaching eight when Eoin Morgan walked in and did not dip. Morgan could not find the boundary in 16 balls and was then stumped. The game appeared up. It wasn't. What followed was epic and will give England much food for thought. For Sri Lanka there was just relief.