US Open - Day 12

James Waterson reports the latest US Open tennis news for Tennis Now. Andy Murray fought it out with John Isner to earn his semifinal spot. He will face Rafael Nadal, who steamrolled Andy Roddick in straight sets. On the other side, a robust Roger Federer faces World #1 Novak Djokovic in a showdown that promises thrills. Caroline Wozniacki takes on Serena Williams, who is riding the comeback express to an impressive degree. Samantha Stosur also faces Angelique Kerber. Michelle Obama dropped by the US Open to hit a few points and speak with kids as part of her initiative against child obesity.