Rafael Nadal celebrates win at Men's singles semifinal is US Open

Rafael Nadal of Spain celebrates his win after the Men's singles semifinal between Rafael Nadal of Spain and Matteo Berrettini at the 2019 US Open in New York, the United States, Sept. 6, 2019. (UNI Photo)

Rafael Nadal returns during Men's singles in US Open

Rafael Nadal of Spain hits a return during the Men's singles fourth round match between Rafael Nadal of Spain and Marin Cilic of Croatia at the 2019 US Open in New York, the United States, Sept. 2, 2019. (UNI Photo)

Caroline Wozniacki of Denmark during US Open Women's Singles

Caroline Wozniacki of Denmark hits a return during the Women's singles second round match between Caroline Wozniacki of Denmark and Danielle Collins of the United States at the 2019 US Open in New York, the United States, Aug. 29, 2019.  

Danielle Collins of US during Women's singles in US Open

Danielle Collins of the United States celebrates during the Women's singles second round match between Caroline Wozniacki of Denmark and Danielle Collins of the United States at the 2019 US Open in New York, the United States, Aug. 29, 2019.

Roger Federer during Men's Singles in US Open

Roger Federer of Switzerland eyes the ball during the Men's singles 2nd round match between Roger Federer of Switzerland and Damir Dzumhur of Bosnia and Herzegovina at the 2019 US Open in New York, the United States, Aug. 28, 2019.