Los Angeles - Defending champion Jack Sock beat top-seeded John Isner 7-6 (7/4), 6-3 on Saturday to reach the final of the ATP clay court tournament in Houston.
America's Sock, seeded fourth, will be trying to become the first player since Andy Roddick in 2001-02 to repeat as the Houston champion when he takes on Argentina's Juan Monaco on Sunday.
Monaco, the 2012 Houston winner, defeated third-seeded Spaniard Feliciano Lopez 6-4, 6-2.
"It's always tough to play a good friend like John," said Sock, whose Houston title remains his only ATP championship.
"But I'm happy to get through. I love playing in this city, on this court."
Isner, struggling with knee trouble, had treatment from a trainer, and Sock, 23, acknowledged he tried to capitalize on that.
"Obviously his knee was bothering him a little bit. I definitely wanted to scrap out points and make him move a lot, test out how he was feeling," he said.
"I was able to be crafty in return games and I guessed right a couple times."
Isner fired 14 aces, but Sock notched the only break of the match in the second set.
Monaco, 32, is seeking his first ATP title since he lifted the trophy in Duesseldorf in 2013.
"I'm really happy to be here again in the final," he said. "I was really focused, consistent from the baseline."
Monaco missed six months with a right wrist injury, slipping from 39th in the world a year ago to his current 146th.
A former top 10 player, Monaco is playing in just his fifth tour-level tournament of the year.
He overcame a few nervy moments to advance. Monaco had three chances to break Lopez and gain a 5-1 lead in the opening set, but the Spaniard held and then broke Monaco to get back on serve before Monaco regained the advantage and took the set.
In the second, Monaco broke Lopez three times to seal the straight sets triumph.
"I think I played a great match," Monaco said.