After losing all of their warm-up games, there was still plenty to concern the Irish management as they were reliant on second-half tries from Tommy Bowe and Rory Best to kill off the Eagles challenge.

But Ireland failed to find a bonus-point try and when Paul Emerick’s late intercept try was proof, according to O’Driscoll, that they cannot afford to rest on their laurels with Tri-Nations  champions Australia next up.

“You have to win games ugly if necessary,” said O’Driscoll. “We can't afford slip-ups or to lose too many games in the pool stages.

"We didn't play well, we really had to fight for our win and we have got a hell of a lot to work on,

“If we're relying on bonus points to get us through the group stages we're going to be in trouble. There were disappointments, but it's not the end of the world.

“There are plenty of things we can work on that we can fix. When you look at individual errors you have to look at your own performance.

 “Today might not have been a thing of beauty but we got across the line and that's the most important thing.

“If everyone can tighten that up, then straight away we'll be on a better footing.

“There were some good aspects to it. We took our tries extremely well.

“But when it finishes on an intercept try and you don't have a chance to reply, it leaves a bitter taste in the mouth.”

After missing his first two kicks, fly-half Jonathan Sexton gave Ireland a slender lead with a penalty in a scrappy first half.

Winger Bowe extended the Irish lead just before half-time, going over after collecting a smart inside pass from Sexton, who also added the conversion.

In the second half, Best took the ball over from a maul and Bowe completed a rare quick passing move from the Irish with a try converted by replacement Ronan O’Gara.

But the match ended on a downer for Declan Kidney’s men when Gordon D’Arcy’s wayward pass put Emerick through for a United States try.