HOUSTON (AP) -- Top-seeded Jack Sock led three Americans into the U.S. Men's Clay Court Championship semifinals Friday night, beating sixth-seeded Feliciano Lopez of Spain 7-6 (6), 1-6, 6-4.
Sock won at Forest Oaks in 2015 for his first ATP Tour title and added victories this year in Auckland, New Zealand, and Delray Beach, Florida.
Sock will face fourth-seeded countryman Steve Johnson, a 6-2, 6-4 winner over fifth-seeded Fernando Verdasco of Spain. Johnson won his lone tour title last year on grass at Nottingham in England.
Ernesto Escobedo reached his first ATP Tour semifinal, outlasting second-seeded John Isner 7-6 (6), 6-7 (6), 7-6 (5) in an all-American match.
The 20-year-old Escobedo gave up 9 inches to the 6-foot-10 Isner, and overcame a 35-10 ace disadvantage against the 2013 tournament winner. Escobedo will face eighth-seeded Thomaz Bellucci of Brazil, a 6-4, 3-6, 6-3 winner over third-seeded Sam Querrey of the United States.