Robbie Keane has told emerging Ireland stars James McCarthy and Jeff Hendrick not to worry too much about their testing 90 minutes work in New York.

The 22-year-old Wigan midfielder and his Derby sidekick, who is a year younger, found themselves thrust into battle which Spain's Sergio Busquets, Xavi and Andres Iniesta at Yankee Stadium during the early hours of this morning. It was a battle they simply could not win despite their tireless efforts to stem the flow, but Keane has insisted they should not be hard on themselves.

“It’s very difficult,” he said. “You can’t judge yourself on these games because you don’t have possession of the ball. In terms of work-rate and showing a lot of energy, you can’t fault them — you couldn’t fault anybody for that. But in terms of keeping the ball, it’s almost impossible because you are playing against a team that just keeps the ball and it is very hard to get it from them.”

Spain ultimately ran out 2-0 winners, but not without a good deal of huffing and puffing and a measure of good fortune thrown in. They could have been out of sight given the possession they had, but had to wait until the 69th-minute for substitute Roberto Soldado to volley them in front.

The defeat was Ireland’s second in their last nine games, and in the circumstances, not unexpected.

However, Spain lived dangerously after the opener, with Ireland substitute James McClean forcing Iker Casillas, who had replaced Victor Valdes after 59 minutes, to make an instinctive save 10 minutes from time. From the resulting corner, Casillas had to react smartly once again to turn Stephen Kelly's near-post header on to the crossbar, but he could do nothing to prevent defender Seán St Ledger from sliding home the rebound, only for a offside flag raised against Simon Cox to come to Spain's rescue.

Ireland's disappointment was complete when Juan Mata added a second goal two minutes from time, but Keane, who played in the 4-0 defeat by Vicente Del Bosque's men at the Euro 2012 finals in Poland last summer, was philosophical in defeat.

“If they have that much possession, they are going to have chances. It’s just a matter of time. It was a shame when they did score, but it’s one of those things. The ‘equaliser’ (from St Ledger) — I think it was just offside, but I think we can take more positives from this game, certainly than from the one a year ago. It was a good experience for a lot of the younger players. The lads conducted themselves very well. They showed a lot of energy. We were playing against the best team in the world, so at times, it’s frustrating because you can’t get the ball from them.

“But in terms of attitude and the way we worked for each other, it was very, very good, so we can take a lot of positives from it.”

Ireland might have, in fact, taken the lead but Conor Sammon's effort from a tight angle after he robbed Gerard Pique of possession was wide of the far upright.

The 26-year-old Derby striker, yet to score a senior goal for his country, will not lose sleep over the one that got away.

“No, there’s no point dwelling on things like that,” Sammon said. “I am delighted to have made another appearance for the team. Yes, it would have been brilliant, it would have capped off a great night to get on the scoresheet — and who knows what way the game would have gone if we had gone in front. But no, I won’t be dwelling on it.

“It was just a long ball up the field and I could see Pique maybe in two minds as to whether I was going to go for it or not. I just caught him off guard and suddenly, I had a few touches and I was in on goal and just looked to place it into that far corner. It was really good to get into that position and it does show that these world-class players are human and make mistakes.”

Sammon did find himself celebrating when after the offside flag denied St Ledger, but accepts the decision was the correct one.

“At the time, I thought there was no way that could be offside — I went off celebrating and didn’t even realise that it was offside. Then James’s (McClean) as well — he did everything right, he got his foot through the ball and struck it well, but credit to the ‘keeper. I don’t know how much he knew about it, but he kept it out of the net.”