Michael Vaughan had no doubt England would beat Sri Lanka even if the rain had not played a decisive part at the Rose Bowl.
"It's not nice when the weather intervenes, but we felt we were controlling the game," said Vaughan.
"To get 250 on that kind of wicket was a tremendous effort especially going into today with only 18 overs left - to score 132 in that space of time."
Vaughan described Andrew Flintoff's 104 as "probably the perfectly timed one-day innings".
He added: "The way he manipulated the field in the middle part and then struck the ball was great to see. Hopefully he can continue that form for another couple of games."
England advanced from 118-3 when rain stopped play on Saturday to 251-7, and then reduced Sri Lanka to 95-5 after 24 overs when the bad weather hit again on Sunday.
"We'd done a bit of homework on the Rose Bowl and we thought 210 to 220 would be a competitive total," Vaughan said.
"When Steve Harmison and Darren Gough have got that white ball they're always going to put the top order under pressure."
Man of the match Andrew Flintoff pronounced himself very satisfied by his fastest century of the year.
"We were only aiming for 220 and the wicket was nipping about a bit but when I was in for the last eight overs we always knew we could get a bit more," he said.
"I rode my luck early on - got dropped a couple of times - but it seems to be that sort of summer as things have gone my way a little bit."
England must now prepare for Tuesday's semi-final against world champions Australia at Edgbaston.
"The Aussies are undoubtedly the best team in the world and have just beaten a good New Zealand side," Vaughan added.
"But we'll certainly go to Birmingham excited by the challenge, looking forward to the game and looking forward to testing our ability against the best team in the world."