By Mike Collett

BLOEMFONTEIN, South Africa (Reuters) - Spain coach Vicente Del Bosque should select his strongest team against surprise packages the United States in the first Confederations Cup semi-final Wednesday.

Del Bosque will call up Iker Casillas in goal with Xabi Alonso and Xavi returning to the midfield and Fernando Torres and David Villa up front.

The European champions will look to extend their unbeaten run to an all-time FIFA recognized record of 36 matches -- along with a world-record extending 15th straight victory.

The unfancied Americans pulled themselves back from the exit door with a 3-0 win over Egypt, which together with Brazil's 3-0 defeat of Italy put the U.S. into the semis.

Spain had expected to play Italy but although the world champions were eliminated they are staying totally focused on the job in hand.

"We are trying to keep winning, keep playing our game," Torres told reporters. "We have ambitions yet and want to win a lot more. After 44 years we won the European championship, now we want a first Confederations Cup for our country."

U.S. coach Bob Bradley said he knew the size of the challenge his side faced.

"Spain are a great team, we played against them in Santander just before they went on to win the Euro," he said. "We know they way they move the ball around and keep possession. Playing them is such a challenge."

The winners will advance to the final in Johannesburg on Sunday where they will face Brazil or hosts South Africa whose semi-final is at Ellis Park Thursday.

The third place playoff is Sunday in Rustenburg.

(Editing by Ed Osmond)