Bloemfontein, South Africa - A day ahead of their semi-final contest with Spain in Bloemfontein the United States revealed that they are on a high mentally following their unlikely escape from Group B but are worried about fatigue in their fourth game in 10 days.

"We're very excited to still be around, but at this point in the tournament you start getting tired," said US all-time top scorer

Landon Donovan Tuesday. "Playing every three days wears on you a little.

"Clearly having another day would have helped," he continued. "We were also playing for our lives in the third game, while Spain had it a little bit easier I think."

Coach Bob Bradley agreed, while saying that the Spanish brand of possession football was an extra worry for tired players.

"When you get to the latter parts of the tournament, you rely on mentality and excitement sometimes and the motivation to do something that hasn't been done yet," said the man who took over the national team spot in 2006 after a group stage exit at the World Cup left his mentor Bruce Arena sacked.

"But the way Spain plays in its simplest form, they move the ball around and in triangles," he said. "Your ability to stay together requires the midfield to stay together and alert and reacting quickly."

Up against the vaunted Spanish midfield, Donovan said the key was knowing when to let them play and knowing when to take chances.

"You know going in that they will have the ball a lot and a big part of playing Spain is not getting frustrated with that," said the LA Galaxy player who mentioned that he would "certainly look at the chance of playing in Spain" if the opportunity came up.

"Sometimes they wear teams down and you feel like you will never get the ball," continued the stand-in captain, who is deputising for the injured Carlos Bocanegra. "But we also want to put them under pressure and see how they react to that."

The US, who currently sit second in CONCACAF qualifying for the World Cup with 10 points from five matches, have a good knowledge of the Spanish team. They lost to them 1-0 last June in Santander in the final warm-up for La Furia Roja before Spain's ultimately successful European Championship campaign.

"There has been a coaching change in the meantime," said Bradley. "But there's no big differences and many of the players are the same. You could tell then that they were the right team at the right time. They were clearly primed and they have created something special."

Bradley, whose son, Michael, starts in midfield and scored against Egypt, picked out dealing with playmaker Xavi and forward Fernando Torres as two keys to the contest.

"In the middle, everything they do starts with Xavi," he said. "In terms of a soccer brain, he's a very complete and super player.

"Torres and his ability to move the ball along the line, along with his speed and balance make him a great striker," he said.

But he was also full of praise for the team that has set a record by winning 15 consecutive international matches

"Spain pose many types of problems obviously," he said. "They have very, very special players, and when you look at their whole team, they have talent in a lot of shapes and sizes. That's essential for a good national team."

But like Donovan, he said the key for the side was to be aggressive against the heavy favourites and make them think at the back.

"We have to play our own football. Our challenge is to be good with the ball and put their defenders under pressure and be aggressive in the right moments and create chances. It will take a complete effort and commitment by the players," he said.(dpa)