During the summer hard-court season Radwańska was twice one match away from becoming the world No. 1. She would lose to Li Na on both occasions, in the quarterfinals of the Rogers Cup and the Western & Southern Open. Radwańska was defeated in the fourth round of the US Open by Roberta Vinci. She again reached the final of the Toray Pan Pacific Open, losing in three sets to Nadia Petrova. She exited the China Open following a quarterfinal loss to Li Na. Radwańska won her opening round-robin match at the WTA Championships, defeating the defending champion Petra Kvitová in straight sets. She then lost a three-set match to Maria Sharapova. She advanced to the semifinals with a victory over Sara Errani, which marked the longest three-set match in the history of the tournament, but exited following a loss to Serena Williams. She then defeated Williams in straight sets during an exhibition in Toronto. At the conclusion of the season, Radwańska won WTA awards for Fan Favorite Facebook Profile and Fan Favorite Video, and was again named Fan Favorite Singles Player.