Jeremy Chardy, of France, serves to Alexander Zverev, of Germany, during the quarterfinal round of the men's tennis competition at the 2020 Summer Olympics, Thursday, July 29, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Alexander Zverev, of Germany, returns to Jeremy Chardy, of France, during the quarterfinal round of the men's tennis competition at the 2020 Summer Olympics, Thursday, July 29, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Jeremy Chardy, of France, cools off during a quarterfinal men's tennis match against Alexander Zverev, of Germany, at the 2020 Summer Olympics, Thursday, July 29, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Alexander Zverev, of Germany, reacts after defeating Jeremy Chardy, of France, in a quarterfinal men's tennis match at the 2020 Summer Olympics, Thursday, July 29, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Alexander Zverev, of Germany, walks on the court during a quarterfinal men's tennis match against Jeremy Chardy, of France, at the 2020 Summer Olympics, Thursday, July 29, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Alexander Zverev, of Germany, returns to Jeremy Chardy, of France, during the quarterfinal round of the men's tennis competition at the 2020 Summer Olympics, Thursday, July 29, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Alexander Zverev, of Germany, returns to Jeremy Chardy, of France, during the quarterfinal round of the men's tennis competition at the 2020 Summer Olympics, Thursday, July 29, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Jeremy Chardy, of France, returns to Alexander Zverev, of Germany, during the quarterfinal round of the men's tennis competition at the 2020 Summer Olympics, Thursday, July 29, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Alexander Zverev, of Germany, serves to Jeremy Chardy, of France, during the quarterfinal round of the men's tennis competition at the 2020 Summer Olympics, Thursday, July 29, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Alexander Zverev, of Germany, returns to Jeremy Chardy, of France, during the quarterfinal round of the men's tennis competition at the 2020 Summer Olympics, Thursday, July 29, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)