Aleksandra Wozniak, of Canada, returns a shot to Li Na, of China, at the BNP Paribas Open tennis tournament, Tuesday, March 11, 2014, in Indian Wells, Calif. (AP Photo/Mark J. Terrill)
Li Na, of China, returns a shot to Aleksandra Wozniak, of Canada, at the BNP Paribas Open tennis tournament, Tuesday, March 11, 2014, in Indian Wells, Calif. (AP Photo/Mark J. Terrill)
Agnieszka Radwanska, of Poland, serves to Alize Cornet, of France, in their fourth round match at the BNP Paribas Open tennis tournament, Tuesday, March 11, 2014, in Indian Wells, Calif. (AP Photo/Mark J. Terrill)
Lu Yen-Hsun, of Taiwan, returns a shot to John Isner, of the United States, at the BNP Paribas Open tennis tournament, Tuesday, March 11, 2014, in Indian Wells, Calif. (AP Photo/Mark J. Terrill)
John Isner, of the United States, returns a shot to Lu Yen-Hsun, of Taiwan, at the BNP Paribas Open tennis tournament, Tuesday, March 11, 2014, in Indian Wells, Calif. (AP Photo/Mark J. Terrill)