Juan Martin del Potro, of Argentina, hits a backhand to Roger Federer during the quarterfinals of the U.S. Open tennis tournament in New York. ( Photo | AP )
Juan Martin del Potro defeats Roger Federer to enter US Open semis
Argentine 28th seed Del Potro defeated the 19-time Grand Slam champion Federer in Arthur Ashe Stadium, a court where Federer has dominated rivals from more than a decade.