England's bid to reach the World Cup quarter-finals is likely to rest on their next two group games during which all-rounder Moeen Ali is confident they can prove they are a "major side".

After belatedly getting off the mark with a 119-run win over Scotland on Monday - when Moeen hit a century - England can all but confirm their place in the knock-out stage with wins over Sri Lanka and Bangladesh over the next fortnight.

Such is the format of the tournament that victory in one of those games might still be enough - provided Afghanistan are beaten in England's final group game - but after their terrible start Moeen is targeting a run of wins.

"We are going out to win the next two," he said.

"That's a very important game [Sri Lanka], if we can win that it will give the team a lot more confidence of being a very good one-day side and a major side in the competition."

England have not claimed back-to-back successes since arriving in the Antipodes and Sunday's clash with Sri Lanka in Wellington - the same venue as their Black Caps mauling - offers a chance to step up a gear.

While victory over Scotland offered as welcomed relief it hardly kept the critics at bay against a nation still searching for a first World Cup win in their third visit to the tournament.

Moeen does not believe, however, that England should feel as though they still have a point to prove.

"I don't feel we are going to have to back it up against Sri Lanka because it was Scotland. We would have to do that anyway," he said.

"Yes, it was Scotland but it was an international game or World Cup game. That brings different pressure.

"If it was Scotland at home, maybe, but this was a very important game with a lot of pressure. We had to go out and perform.

"We saw Scotland gave New Zealand a decent game - there are lots of dangerous sides and these teams are not as easy as they used to be."

England lost their pre-Christmas one-day international series in Sri Lanka 5-2, but have reason to think they can beat them in New Zealand conditions.

After being overwhelmed by the Black Caps in their recent ODI series in the same conditions, Sri Lanka have made a stuttering start to the World Cup. They were easily cast aside by New Zealand in their opener before sneaking past Afghanistan last time out.

Moeen knows England can ill afford to underestimate a team including the likes of world-class talents such as Kumar Sangakkara, Mahela Jayawardene and Angelo Mathews, but suspects keeping them quiet with the bat will be critical.

"Obviously we lost to them in Sri Lanka. We know a lot about them now having played against them quite a bit last year," he said.

"They have some really good batters and that will be the key, their four main batters, (Tillakaratne) Dilshan, Sangakkara, Mahela and Mathews.

"We saw the other day Mahela is in good form so we are going to have to bowl really well and obviously bat well against them. It will be a close game, a tight game so we will have to be at our best to beat them."

Moeen will have a key part to play with the ball in Wellington with his handy off-spin as England's option as a fifth bowler.

He claimed two wickets against Scotland in Christchurch, but is still to reveal his full repertoire with his 'doosra' so far kept in cotton wool.

The 27-year-old has been practising it in the nets, but he is not yet ready to unveil it again in competitive action.

"No, not really," he said.

"I bowled a couple in the nets the previous day just at Ravi (Bopara) because he was trying to smash it, but I have not really thought about it."