The Argentine, ranked No. 156 in the world, won the match when the American double-faulted on match point. Zabaleta squatted to his knees and covered his eyes with his hands before getting to go shake Blake's hand.

The wind made serving and returning serve "really tough," Zabaleta said.

"I play very focused and played very good the important points because the match was so close," he said. "I feel really happy and I enjoy this moment."

Zabaleta, who won two matches to qualify, plays Ivo Karlovic of Croatia in tomorrow's final. The Croat is ranked No. 108.

Before beating Blake, who's ranked No. 9 in the world, Zabaleta defeated defending champion Mardy Fish of the U.S., the No. 4 seed, and knocked off last year's runner-up, fifth-seeded Jurgen Melzer of Austria, in the quarterfinals.

Blake had three set points in the tiebreaker but failed to capitalize on them. On the last one, Zabaleta hit a forehand winner up the line to make it 7-7.

Zabaleta hit an overhead winner to take him to match point.

His double fault had nothing to do with the wind, Blake said

"Took my eye off of it, that's it," Blake said. "You can't do that. I was already thinking about the next shot."

Zabaleta broke Blake in the 11th game of the first set and held serve to take the set 7-5.

Blake had never made it past the quarterfinals in Houston, which is hosting the event for the last time this year. He lost in the second round in 2001, in the quarterfinals the next four years and in the first round in 2006.

The American has had a roller-coaster year, starting 11-1 before losing six of his next nine matches. Today's loss ended a five-match win streak, including two that helped the United States beat Spain in Davis Cup play last weekend.