Joe Root acknowledges he and his team-mates have yet to register a "complete" performance in Sri Lanka but insists they are still capable of stringing together three back-to-back wins to sneak a series success.

Joe Root acknowledges he and his team-mates have yet to register a "complete" performance in Sri Lanka but insists they are still capable of stringing together three back-to-back wins to sneak a series success.

Stand-in captain Eoin Morgan conceded England perhaps had one eye on World Cup preparation as well as the here and now after they fell 3-1 behind with three to play with defeat by six wickets in Colombo on Sunday.

But with Alastair Cook back from his over-rate ban, the stakes are high in the short as well as medium term and selection at Pallekele will surely be made exclusively to try to keep the series alive rather than laying the ground for this winter's global tournament.

Asked if England can still edge a 4-3 verdict over the next week, Root said: "There's no reason why we can't.

"I think we've shown in every game at some point along the way that we are capable of doing that. The thing for us now is to make sure we put it into one complete performance."

That did not happen, by Root's admission, even at Hambantota last week when his and Jos Buttler's unbroken stand eventually proved the match-winner.

"Now's the time for us to step up and start putting in performances, and this is a great opportunity for us to do that under pressure before the World Cup," he added.

"Even the game we did win, we didn't play at our absolute best - which, again, is promising.

"You don't want to talk about being promising all the time."

England chose all three seam-bowling all-rounders in Colombo on Sunday when it seemed James Tredwell's off spin may have fitted the bill better on a slow pitch.

That was rationalised by Morgan as longer-term thinking, to check the progress of those who might be picked later this month to head to Australia and New Zealand in the new year.

So will there be more experimentation in the fifth ODI?

"No, we want to win this series," said Root.

"We know that, looking at the wicket here, the conditions might be slightly different to Colombo - and if we can get level going back into that last game, it's going to be a great finish.

"This sort of pressure is good practice for a World Cup. Preparing for that, this is as close as we can get.

"We're just going to try to make sure we put in two really good performances here and finish off the series well."

Root has yet to reach 50 on this tour, but has contributed handily nonetheless - alongside Ravi Bopara, Buttler and then in England's highest stand here so far with new number three James Taylor.

He said: "It's just getting in, and then getting out, twice now.

"So I hope I can go and make some really big scores and win some games of cricket."

England's batsmen will have to contend with another challenge, after the International Cricket Council cleared Sachithra Senanayake's bowling action.

The off-spinner, who controversially ran out Buttler backing up at Edgbaston last summer, was suspended soon afterwards because of his suspect action.

Sri Lanka have now confirmed his inclusion in place of the injured Rangana Herath for the next two ODIs.

"Whoever we come up against, we want to make sure we're ready," said Root.

"If he's playing, we'll have to find a way to deal with that.

"He's a very good international player, and his stats say that. He's a big part of their side. If he comes back in, we'll have to just make sure we've got ways of combating him."