Fourth-seeded defending champion Jack Sock has beaten John Isner in an all-American semi-final at the US Men’s Clay Court Championship in Houston.

Sock, who defeated the top seed 7-6 (4) 6-3, will face Argentina’s Juan Monaco in the final on Sunday at River Oaks.

The 23-year-old Sock has won 16 consecutive sets in the event dating to his first-round match last year.

“I love playing in this city, on this court. I love the clay,” Sock said.

“There’s something about that little stadium there, it’s a great atmosphere.”

The 32-year-old Monaco, the 2012 winner, downed third seed 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.”

Isner had treatment on his left knee twice during the match and admitted to feeling a little dinged up.

“I haven’t been healthy in a while. We’ll see what I need to do. Got to pay the piper eventually,” Isner said.