John Isner's 57 aces in the tournament is just three short of the record set by Pete Sampras in 2002
Pat Sullivan/AP

John Isner got his big serve working after a slow start to reach the final of the U.S. Men's Clay Court Championship, beating defending champion Juan Monaco of Spain 1-6, 6-4, 6-4 on Saturday.

The fifth-seeded American will face Nicolas Almagro, the top-seeded Spaniard who needed only 58 minutes to beat American wild-card Rhyne Williams 6-2, 6-1.

Isner finished with nine aces for a tournament total of 57, three short of the record set by Pete Sampras in 2002.

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