Captain Alastair Cook said England must build on their success after securing a 3-2 one-day series win over Sri Lanka.
Despite clinching victory at Old Trafford in dramatic fashion on Saturday, he believes England are a long way from achieving their targets.
"We are a long way off the level we want to be at," said new skipper Cook.
"The things we talked about as a team at the beginning of the series are going to take time to work out but this is a step in the right direction."
The series was Cook's first on home soil after his appointment as captain of the one-day side, and the 26-year-old praised his team's character after they stood firm to hold off Sri Lanka's fightback in the final match.
"That's the first time I've had a really tight scenario in my eight games as one-day captain, and I thought we handled it well," added Cook, who also led the side in Bangladesh in 2010.
"I think the most pleasing aspect is the way we fought back from 2-1 down in the series.
"Everyone was writing us off, and we've played well in these past two games in all conditions on spinning wickets and flat wickets."
Cook's place in the side had been questioned before the series but he responded with 298 runs at an average of 74.50 and a strike rate of 96.75 in the five matches.
The Essex player's form ensured he was named player of the series but he denied he had been motivated by those who questioned whether he was worth his place.
"I have improved a little bit," said Cook. "It is always nice to score runs but you don't do it to prove critics wrong, you do it to help England win.
"When you pull on an England shirt, people are always going to have their own opinions. I don't do it to prove anyone wrong. I do it for the satisfaction that we got in that final half-hour of the game, and you can't replicate that. That's why you play the game."
England caused a stir before start of play when they dropped their Twenty20 captain Stuart Broad to make way for slow-bowling all-rounder Samit Patel, opting to retain the inexperienced Jade Dernbach.
Cook explained it was a decision taken partly because of conditions in Manchester, but hinted Broad's moderate run of form had played its part too.
"We wanted to play two spinners," he said. "We picked Jade ahead of Broady, and that's why we changed it.
"It doesn't mean that Broady won't come back in. It's obviously a tough pill for him to swallow, but his record in one-day cricket is outstanding.
"Just because he hasn't taken the wickets he would have liked doesn't mean he won't be back."
Cook's opposite number Tillakaratne Dilshan said: "We lost the Test series in one hour and again in this one-day series lost three matches in about the first six overs of our batting.
"I think we can be a much better side than that."