John Isner and Juan Monaco each won their semifinal matches on Saturday and will now meet in the final at the U.S. Men's Clay Court Championship.

The second-seeded American Isner hammered 13 aces and saved all eight break chances by Spain's third seed Feliciano Lopez to battle back for a marathon 6-7 (5-7), 7-6 (7-4), 6-3 decision at River Oaks Country Club.

Lopez hit nine aces of his own, but also suffered four double faults in defeat as Isner improved to 7-0 on clay this season.

An American has now reached the final at this tournament for 11 of the past 12 years, including the last five.

His opponent will be Monaco after the fourth-seeded Argentine outlasted American Michael Russell, 5-7, 6-1, 6-4 in a nearly two and a half hour long match.

After having his serve broken twice while committing two double faults in the first set, Monaco did not face a break chance in the second and smacked two aces in the third set while breaking Russell twice to move on.

Monaco will be in search of his fifth ATP title, while Isner will be trying for his fourth.

The winner of this $522,000 tournament will collect $71,900.