England captain Andrew Strauss admitted the loss of Marcus Trescothick had been the turning point as Sri Lanka claimed victory by two runs in the Twenty20 International at the Rose Bowl.
Trescothick had reached 72 when he was run out with England appearing to be on course to collect the 12 runs needed from the last nine deliveries.
However, England's chances of victory immediately receded with the Somerset opener's departure and they fell just short, finishing two runs short of their target on 162 for five.
Strauss told Sky Sports: "Twenty20 produces games like these.
"It was a great day's cricket but we are disappointed to come off as the losing side.
"We looked as through we were going to win but then Tres' run-out was key.
"Tres has the experience to battle on, he did a great job and it was a shame to lose him."
Strauss admitted the team had been affected by the early injury sustained by Ed Joyce.
"We came out pretty pumped up and looking forward to the game," he said.
"It was terrible to watch but hopefully it is better than it looked.
"It was a dislocated ankle but it popped back in."
The day-night match was a precursor to the NatWest one-day internationals between the teams, with England set to field a mainly untried team.
"We are a young inexperienced side but there a lot of guys with something to prove," said Strauss.
"We have five matches and we have got to prove we are a match for Sri Lanka and win it."
Opposite number Mahela Jayawardene was thrilled to have claimed victory after his team had suffered against county opposition.
"It was great. We made a lot of mistakes to begin with," he said. "We made a lot of mistakes in the middle....
"It's all part of the preparation. You make the mistakes and get those sorted out and it's the big matches that really count."