Coach Marvan Atapattu says Tuesday's Twenty20 victory over England has given them huge confidence for the forthcoming one-day international series.
Sri Lanka beat England by nine runs in the one-off Twenty20 match at The Oval.
And the teams return to the same venue for the five-match Royal London One-Day International series on Thursday with Sri Lanka buoyant.
"To come and beat England in England was a great thing," said Atapattu.
"We needed that win to tell ourselves we are good enough to compete against these guys on their home soil."
Atapattu senses England may be vulnerable after their dreadful Ashes winter and following several management changes.
That includes the return of Peter Moores for his second stint as head coach whilst his number two will be Paul Farbrace, recruited by the ECB from Sri Lanka where he was head coach.
"We believe if we play our best cricket, we can put any team under pressure," Atapattu said.
"From England's point of view, they have gone through a couple of shaky series and have a new management and a couple of new players.
"They could be different in their approach.
"But we are most concerned with how we perform in English conditions to meet the challenge."
Skipper Angelo Mathews meanwhile admits he is surprised Alex Hales will not be in the England line-up.
The Nottinghamshire opener top-scored with 66 on Tuesday night, and back at the World Twenty20 he smashed a memorable century against the Sri Lankans - who would go on to win the tournament.
But he was left out of the 50-over squad.
"I was a bit surprised [he was not in the ODI squad]," said the all-rounder.
"Alex has been playing really well and has scored a lot of runs against us. But England have a really good batting line-up. Without Alex, they've got seven or eight really good batsmen and we've got to deal with them all."
Atapattu batted for years alongside Sanath Jayasuriya, one of the most destructive batsmen in world cricket before his retirement.
And one man Atapattu believes has the capability to go on all-out attack against his team is England captain Alastair Cook - not a player usually associated with cavalier play.
"There are a couple of times Alastair has done that," he said. "Not too many batsmen have done it as consistently as Sanath did.
"But I won't be surprised if somebody hits form. Why not? With field restrictions, fast outfields and good pitches, batsmen have more chances to be like Sanath these days.
"Modern-day cricket...encourages and needs someone to be explosive. But it has to come naturally to you, be inherent. It's not something you can bring out in a day or two."
Watch England play Sri Lanka live on Sky Sports 2, with coverage from 12.30pm.