Article Photos: S. Williams, Federer ease into US Open's 4th round



Agnieszka Radwanska, of Poland, returns a shot to Serbia's Jelena Jankovicin the third round of play at the 2012 US Open tennis tournament, Saturday, Sept. 1, 2012, in New York. (AP Photo/Kathy Willens)

Agnieszka Radwanska, of Poland, returns a shot to Serbia's Jelena Jankovicin the third round of play at the 2012 US Open tennis tournament, Saturday, Sept. 1, 2012, in New York. (AP Photo/Kathy Willens)