Women's tennis

Rafael Nadal, of Spain, returns a shot to Daniil Medvedev, of Russia, during the men's singles final of the U.S. Open tennis championships Sunday, Sept. 8, 2019, in New York. (AP Photo/Eduardo Munoz Alvarez)

Bianca Andreescu, of Canada, holds up the championship trophy after defeating Serena Williams, of the United States, in the women's singles final of the U.S. Open tennis championships Saturday, Sept. 7, 2019, in New York. (AP Photo/Adam Hunger)

Bianca Andreescu, of Canada, lays on the court after defeating Serena Williams, of the United States, during the women's singles final of the U.S. Open tennis championships Saturday, Sept. 7, 2019, in New York. (AP Photo/Sarah Stier)

Bianca Andreescu, of Canada, waits for the return from Serena Williams, of the United States,during the women's singles final of the U.S. Open tennis championships Saturday, Sept. 7, 2019, in New York. (AP Photo/Sarah Stier)

Rafael Nadal, of Spain, returns a shot to Matteo Berrettini, of Italy, during the men's singles semifinals of the U.S. Open tennis championships Friday, Sept. 6, 2019, in New York. (AP Photo/Eduardo Munoz Alvarez)

Serena Williams, of the United States, returns a shot to Elina Svitolina, of Ukraine, during the semifinals of the U.S. Open tennis championships Thursday, Sept. 5, 2019, in New York. (AP Photo/Seth Wenig)

Serena Williams, of the United States, follows through on a return to Qiang Wang, of China, during the quarterfinals of the U.S. Open tennis tournament Tuesday, Sept. 3, 2019, in New York. (AP Photo/Seth Wenig)

Bianca Andreescu, of Canada, reacts after defeating Elise Mertens, of Belgium, during the quarterfinals of the U.S. Open tennis tournament Wednesday, Sept. 4, 2019, in New York. (AP Photo/Seth Wenig)

Matteo Berrettini, of Italy, reacts after winning the fifth set tie break for victory against Gael Monfils, of France, during the quarterfinals of the U.S. Open tennis championships Wednesday, Sept. 4, 2019, in New York. (AP Photo/Frank Franklin II)

Roger Federer, of Switzerland, returns to Grigor Dimitrov, of Bulgaria, during the quarterfinals of the U.S. Open tennis tournament Tuesday, Sept. 3, 2019, in New York. (AP Photo/Charles Krupa)