USA coach Bruce Arena insisted he was not too concerned about his side's sub-standard display in Tuesday's 1-0 friendly defeat against Morocco.

A last-minute goal from Mohamed Madihi secured victory for the visitors in Nashville, but Arena remains confident his team will be ready for their World Cup opener against Czech Republic on June 12.

"First of all I think our opponents played a better game than us tonight," he told US Soccer's official website.

"They had a definite game plan and the objective was to keep the US team off the scoreboard and they certainly accomplished that.

"They shortened the game with fouling, delaying and both are fair and within the rules of the game. They did a very solid job.

"They caught us at the end of the game with a mistake and got a goal. I think they would have been very, very happy with zero-zero.

"On the other end, we weren't sharp. We were a little leg weary, a little over-trained at this point. If I had to do it all over again, I wouldn't change anything we've done.

"Our objective is still to look ahead to June 12 and not necessarily these games, although we certainly would have liked to have a positive result tonight."

The USA will now play warm-up games against Venezuela on May 26 and Latvia on May 28 before departing for Germany on June 1.