Peter Moores is calling on England to produce a "complete" performance at Edgbaston to kickstart his new era with a series victory at the first attempt.
England, who have twice led the Royal London one-day international series against Sri Lanka, face a decider against on Tuesday after the tourists held their nerve to inch a seven-run win at Lord's two days ago.
For Moores, the first man to return to the job as England head coach, a win will be an obvious initial vindication as he and captain Alastair Cook seek to set a new tone following last winter's Ashes whitewash.
England's victories to date, at The Oval and then Emirates Old Trafford, were separated by a near record defeat at Durham - and then even Jos Buttler's brilliant maiden hundred at HQ was not enough to stop Sri Lanka levelling the score again.
Asked about the significance of a series win, 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 lot 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 tomorrow.
"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."