US Open men's singles quarterfinal watch: Matteo Berrettini vs. Gael Monfils

Gael Monfils of France reacts during the men's singles quarterfinal match between Matteo Berrettini of Italy and Gael Monfils of France at the 2019 US Open in New York, the United States, Sept. 4, 2019. (Xinhua/Liu Jie)