BELGRADE, Serbia — Sam Querrey and John Isner won semifinal matches Saturday at the Serbia Open, setting up the first all-American ATP clay-court final in Europe since Jim Courier defeated Andre Agassi for the 1991 French Open championship.

Querrey, seeded third, routed 18-year-old Serbian wild card Filip Krajinovic 6-1, 6-2. Isner, seeded second, beat fourth-seeded Swiss Stanislas Wawrinka 7-5, 7-5.

Querrey needed just 51 minutes to dispatch Krajinovic, who was playing his first ATP semifinal. Querrey will try to win his fourth ATP title and first on clay.

"I played well tonight, hope I can repeat it tomorrow," he said.

Isner broke Wawrinka in the 12th game of each set to reach his fourth career final and his first in Europe.

Wawrinka had two double-faults in the last game of the first set. In the second set, Isner wasted one match point at 5-4, but converted his second when the Swiss player sent a forehand into the net.

Krajinovic played in his first ATP semifinals. He advanced on Friday when defending champion Novak Djokovic retired due to breathing problems he said were caused by allergies.

Djokovic said on Saturday he was withdrawing from next week's Madrid Open because of the problem.