Caroline Wozniacki, of Denmark, hits a return to Ekaterina Makarova, of Russia, during the U.S. Open tennis tournament, Wednesday, Aug. 30, 2017, in New York. (AP Photo/Julio Cortez) - Easy Branches

Caroline Wozniacki, of Denmark, hits a return to Ekaterina Makarova, of Russia, during the U.S. Open tennis tournament, Wednesday, Aug. 30, 2017, in New York. (AP Photo/Julio Cortez)

Caroline Wozniacki, of Denmark, hits a return to Ekaterina Makarova, of Russia, during the U.S. Open tennis tournament, Wednesday, Aug. 30, 2017, in New York. (AP Photo/Julio Cortez)