Juan Martin del Potro of Argentina, the 7th seed in the men's draw at the U.S. Open men's singles tennis tournament, advanced to the third round with a victory over unseeded American Ryan Harrison on Friday.

Del Potro won in four sets, 6-3, 6-2, 2-6, 6-2, in a match that took two hours, 34 minutes. Del Potro won 7 of 10 break points and committed 10 fewer unforced errors than Harrison, a 20-year-old from Austin, Texas who has never gotten past the second round at a Grand Slam event.

Del Potro faces countryman Leonardo Mayer in the third round. Mayer defeated Tommy Robredo of Spain in four sets in their second-round match.

Del Potro, the 2009 U.S. Open champion, lost in the third round last year and couldn't play in 2010 after surgery. His bracket includes No. 2 seed Novak Djokovic and fourth-seeded David Ferrer. More information and scores can be found at the U.S. Open website.

For all the latest news, results and analysis of the 2012 U.S. Open, make sure you check out SB Nation's dedicated tennis hub.