Diego Schwartzman, of Argentina, serves to Tomas Machac, of the Czech Republic, during second round of the men's tennis competition at the 2020 Summer Olympics, Tuesday, July 27, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Tomas Machac, of the Czech Republic, returns to Diego Schwartzman, of Argentina, during second round of the men's tennis competition at the 2020 Summer Olympics, Tuesday, July 27, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Diego Schwartzman, of Argentina, returns to Tomas Machac, of the Czech Republic, during second round of the men's tennis competition at the 2020 Summer Olympics, Tuesday, July 27, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Tomas Machac, of the Czech Republic, returns to Diego Schwartzman, of Argentina, during second round of the men's tennis competition at the 2020 Summer Olympics, Tuesday, July 27, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Diego Schwartzman, of Argentina, returns to Tomas Machac, of the Czech Republic, during second round of the men's tennis competition at the 2020 Summer Olympics, Tuesday, July 27, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Diego Schwartzman, of Argentina, returns to Tomas Machac, of the Czech Republic, during second round of the men's tennis competition at the 2020 Summer Olympics, Tuesday, July 27, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Diego Schwartzman, of Argentina, serves to Tomas Machac, of the Czech Republic, during second round of the men's tennis competition at the 2020 Summer Olympics, Tuesday, July 27, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Diego Schwartzman, of Argentina, returns to Tomas Machac, of the Czech Republic, during second round of the men's tennis competition at the 2020 Summer Olympics, Tuesday, July 27, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Tomas Machac, of the Czech Republic, returns to Diego Schwartzman, of Argentina, during second round of the men's tennis competition at the 2020 Summer Olympics, Tuesday, July 27, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Diego Schwartzman, of Argentina, returns to Tomas Machac, of the Czech Republic, during second round of the men's tennis competition at the 2020 Summer Olympics, Tuesday, July 27, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Diego Schwartzman, of Argentina, returns to Tomas Machac, of the Czech Republic, during second round of the men's tennis competition at the 2020 Summer Olympics, Tuesday, July 27, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Diego Schwartzman, of Argentina, serves to Tomas Machac, of the Czech Republic, during second round of the men's tennis competition at the 2020 Summer Olympics, Tuesday, July 27, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)