Fourth-seeded defending champion Jack Sock beat top-seeded John Isner 7-6 (4), 6-3 on Saturday in an all-American semifinal in the U.S. Men's Clay Court Championship.

Sock will face Argentina's Juan Monaco in the final Sunday at River Oaks. The 32-year-old Monaco, the 2012 winner, beat third-seeded Feliciano Lopez of Spain 6-4, 6-2.

"I'm really happy to be here again in the final," said Monaco, an eight-time winner on the ATP Tour. "I was really focused, consistent from the baseline."