Alastair Cook's future as England ODI captain appears to be in the balance after another series loss left coach, Peter Moores, unable to guarantee his place in the World Cup side.

England succumbed to a 90-run defeat in the sixth ODI of the series in Pallekele giving Sri Lanka an unassailable 4-2 lead with one match to play. It means England have lost six of their last seven ODI series and nine of their last 12 ODIs.

Cook endured another miserable match, failing once again with the bat - he has now scored one half-century in his in his last 21 ODI innings. He also dropped a straightforward catch offered by Kumar Sangakkara when the batsman had 41. Sangakkara went on to score a match-defining century.

It left Moores unable to offer anything but equivocal support after the match. Admitting Cook "needs runs" he also stated that, as one of four selectors, it would be presumptuous for him to offer a definite opinion and that, as usual, the management will "review everything" after the series.

Asked by Sky Sports whether Cook would be captain at the World Cup, Moores replied: "We review everything at the end of every series, we've always said that.

"We've had many things happen on this series and we've got a very new batting line-up with people like Moeen Ali and James Taylor coming in and doing well.

"We make no bones that we're passionate to try and get our best side to go out and win a World Cup. Cook needs runs but he's also had some great times as an England player. He's in a tough patch at the moment but that's something he's working hard to get out of."

Cook was more confident about his future, however. Asked afterwards if he believed he would be the man leading England at the World Cup, Cook said: "Yes."

"It's clearly been a tough day," he said. "We came in with high hopes, especially with the way we played at the same ground two days ago. So it's been a frustrating day all round and it doesn't make the job any easier.

"I'm not scoring the runs I would like, it's not a great place to be as a captain, you want to lead from the front and when it's not happening for you it's frustrating. I'm a better player than I'm showing at the moment and I've just got to keep going."

Despite their abject run of form over the last 18 months, Cook said he felt the side had made improvements but that another series defeat was a "reality check".

"I think we've actually made some good strides on this tour in one-day cricket," he said. "The way the lads have gone about it has been fantastic. Today is a really tough day for everyone involved in an England shirt. We played so well last game and to play nowhere near as well as that is incredibly frustrating because we need to be consistent. We've always struggled a bit with our one-day and hopefully we're making steps to get better at it. But this is obviously a reality check."

While Moores celebrated the opening spells of Chris Woakes and Steven Finn, he admitted that England's death bowling allowed Sri Lanka to "get away" from them.

"It's disappointing," he said. "We came here thinking we could draw the series level, but we were outplayed in probably all three departments. We dropped catches and we lost too many wickets early despite being up with the rate.

"Bowling, we did well in the first 10 overs, but towards the end of the innings we need to make sure our plans are a bit clearer, a bit simpler. We also didn't choose the right lengths with the ball at times. We did some good things at times, but some costly errors let them get away from us."