Chasing a modest 230, the Sri Lankans got home with 63 balls to spare as Tharanga and Dilshan smashed unbeaten centuries, their second in the tournament.
"It looked easy out there, but you need a special performance to win big games and today Dilshan and Upul Tharanga combined to give us that little spark of inspiration," the Sri Lankan captain told reporters at the post-match press conference.
"They were ruthless and magnificent. It wasn`t easy for them, you know the wrapping up of it. They could have thrown it away, but it showed how hungry they were to finish it off," Sangakkara added.
Sri Lanka did well to restrict England to 229 for six in their 50 overs and Sangakkara said losing the toss they were determined to keep the Andrew Strauss-led side below the 250-run mark.
"Losing the toss you want to keep the opposition for a manageable total. We were targeting to keep them below 250 and I thought we did exceptionally well to keep them below that.
Maybe an improved performance on the field could have helped us to keep them little lower than that," he said.
The only drawback for the Sri Lankans during the game was dropping three catches, all of Eoin Morgan.
"There were three people who missed catches and that`s the way the game goes. We need to brush up our fielding. We can`t afford to give one player that many chances," Sangakkara said.