Ernesto Escobedo outlasted second-seeded John Isner 7-6 (6), 6-7 (6), 7-6 (5) on Friday in the U.S. Men's Clay Court Championship to reach his first ATP Tour semifinal.
The 20-year-old Escobedo gave up 9 inches to the 6-foot-10 Isner, and overcame a 35-10 ace disadvantage in the all-American opening quarterfinal at Forest Oaks. Isner won the 2013 tournament.
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.
In the other semifinals, top-seeded Jack Sock of the United States faced sixth-seeded Feliciano Lopez of Spain, and fourth-seeded Steve Johnson of the United States met fifth-seeded Fernando Verdasco of Spain.
Sock won the tournament in 2015 for his first ATP Tour title and added victories this year in Auckland, New Zealand, and Delray Beach, Florida.