Federer has won 5 US Opens however his fading form has many backing Nadal instead.
Rafael Nadal wants a career Grand Slam and to complete the feat, he needs only to win the US Open. Nadal has never won the title in Flushing Meadows but with Roger Federer fading and with defending champion Juan Martin Del Potro out of commission, a fantastic opportunity for Nadal is ripe for the picking later this summer. http://www.crunchsports.com/category/Tennis/US-Open-2010-Odds--Roger-Federer-a-co-favorite-with-Rafael-Nadal-201007150002/