Roger Federer has won the last four U.S. Open titles, but he won't be the favorite when the tournament starts tomorrow at the USTA National Tennis Center in Flushing. That honor will go to Rafael Nadal, the new world No. 1 and winner of the French Open, Wimbledon and the Olympics this summer. Federer, 27, has looked mortal or worse this season, and Nadal, 22, has peaked while displaying an all-surface versatility that had eluded him in previous summers. For the first time since the 2004 Australian Open, Federer will not be the top seed at a Grand Slam event. more ›