Aug. 9, 2009 (United Press International) -- Top-seeded Andy Roddick will play defending champion Juan Martin del Potro in Sunday's Legg Mason (NYSE:LM) Tennis final.

Roddick, a three-time winner of the event, advanced to the final by beating fellow American John Isner 6-7 (3-7), 6-2, 7-5. Roddick won the tournament in 2001, 2005 and 2007.

Del Potro, a 20-year-old Argentine, will be seeking back-to-back titles. He defeated fourth-seeded Fernando Gonzalez 7-6 (7-2), 6-3 in the other semifinal matchup earlier Saturday.

Del Potro will try to become the first repeat winner of this event since American Andre Agassi, who won in 1998 and 1999.

The 2009 Legg Mason champ will collect $300,000.