England and Sri Lanka meet at Edgbaston on Tuesday for the deciding match of a wildly fluctuating one-day international series.
The five-match series is level at 2-2 with England's victories to date, at The Oval and then Emirates Old Trafford, separated by a near record defeat at Durham.
England fell just short of a target of 301 at Lord's on Saturday despite Jos Buttler's 61-ball maiden hundred.
Asked about the significance of a series win, England coach Peter Moores said: "It would be great. We'll treat it like a final.
"We know we have a World Cup coming up, and there will be a lots of big games in that.
"It would be great to win the series, and we'll put everything we've got into it."
England's performances so far have lurched to extremes, especially at Durham and Manchester.
Moores added: "So far through the series, we haven't quite put the complete game together.
"The closest one was at the Oval. I hope we'll do that on Tuesday.
"We've shown we can beat them, and we can be very competitive.
"We're pretty confident that if we play well we have got a good chance of a win."
England have no fitness worries and are likely to name an unchanged team, while Sri Lanka's preparations have been disrupted by the news that spinner Sachithra Senanayake was reported to the ICC by the match officials for a suspected illegal bowling action following the Lord's victory.
Senanayake must undergo testing within 21 days but remains available in the meantime.
England squad: Cook (capt), Anderson, Ballance, Bell, Bopara, Buttler (wkt), Carberry, Gurney, Jordan, Morgan, Root, Tredwell, Woakes
Sri Lanka squad: Mathews (capt), Thirimanne, Chandimal, De Siva, Dilshan, Herath, Jayawardene, Kulasekara, Malinga, Mendis, K Perera, T Perera, Prasad, Priyanjan, Sangakkara (wkt), Senanayake