A look at Monday's play at the $21.6 million U.S. Open tennis championships:
WEATHER: Mostly sunny, breezy and mild. High of 79.
ATTENDANCE: 24,821.
MEN'S RESULTS: No. 6 Juan Martin del Potro upset No. 1 Roger Federer in five sets to win his first Grand Slam singles title in his first attempt. For Federer, it was his sixth loss in 21 Grand Slam finals and first at the U.S. Open since 2003.
WOMEN'S RESULTS: No. 4 Serena Williams and Venus Williams won their third Grand Slam doubles title this year, beating top seeds Cara Black and Liezel Huber. It was the sisters' 10th career Grand Slam title.
STAT OF THE DAY: Roger Federer struggled with his serve all night, hitting 11 double faults, five more than his previous worst in a Grand Slam final.
QUOTE OF THE DAY: ``Five was great, four was great, too. Six would have been a dream, too. Can't have them all.'' - Roger Federer, whose loss ended his U.S. Open title streak at five.