Ireland are heading to the World Cup on the back of four defeats in as many warm-up matches but Paul O'Connell insists now is not the time to abandon all hope of the team playing well in New Zealand.

The Irish rounded off their preparations with a 20-9 loss to old rivals England here on Saturday, a defeat made all the worse by the sight of flank David Wallace suffering a World Cup-ending knee injury.

This reverse, which saw England score tries though Manu Tuilagi and Delon Armitage while Ireland failed to cross their opponents' line, came on the back of a loss to Scotland and away and home defeats by France.

But O'Connell, who led Ireland on Saturday in the absence of regular captain Brian O'Driscoll, left out from this match as a precaution to nurse a shoulder injury, said the situation was still retrievable.

"The game against England in March (when Ireland won 24-8 in Dublin to deny Martin Johnson's men a Grand Slam) was a good game for us, but it came on the back of us having a few disappointing performances - and we're back in that place now," O'Connell told reporters.

"We know what the basics we need to get right for us to do well are, what we need to do to perform at a high level," he said.

"This defeat puts us in a position where we will learn a lot and, if we can get things right, we won't be in a bad place. It's been a disappointing four weeks, but we're confident when we get to New Zealand we can perform," added the big lock.

The Irish start their World Cup campaign against a United States team coached by ex-Ireland boss Eddie O'Sullivan on September 11.

However, Declan Kidney's side will, at the very least, be expected to qualify out of a group also featuring Australia, Italy and Russia and so improve on a first-round exit in France four years ago.

"We've excellent players, we know how good we can be, with the experience we have we can produce it in the World Cup," O'Connell said.

Ireland were repeatedly second best at the breakdown on Saturday and struggled to come to terms with the way in which Welsh referee Nigel Owens policed this always contentious area of the game.

"We like to think of the breakdown as a good part of our game," said O'Connell. "They (England) put numbers in, hit it hard and got away with it. A lot of it was illegal but it achieved what it wanted to achieve - they slowed down a lot of our ball."

Although Wallace was ruled out of the World Cup, with Shane Jennings called up in his place, Ireland coach Declan Kidney was confident Jamie Heaslip (concussion) and Jerry Flannery (shin) would both be fit for the tournament following injuries against England.

But prop Cian Healy, who took blows around the eyes, has had his departure for New Zealand delayed on medical grounds and could miss the opener against the United States.

Many pundits feared Ireland were inviting injury trouble playing the ever-physical England after naming their World Cup squad but Kidney said: "Well, I knew Australia were playing New Zealand this (Saturday) morning, so we needed games to get going.

"We want to compete at the highest level and England and France are the perennial semifinalists and finalists - so we know where we are now.

"We've lost four games in a series, the results are bitterly disappointing. I won't come up with a huge amount of excuses, or camouflage over them. We're here to get results and we'll keep working," he promised.