Juan Martin del Potro dethroned five-time defending US Open champ Roger Federer today, the New York Times reports, earning his first Grand Slam title with a 3-6, 7-6 (5), 4-6, 7-6 (4), 6-2 victory. Del Potro, a 20-year-old from Argentina, had never beaten Federer, the 28-year-old Swiss who has won a record 15 major crowns. (More Juan Martin del Potro stories.)