Novak Djokovic, of Serbia, returns to Alejandro Davidovich Fokina, of Spain, during the third round of the men's tennis competition at the 2020 Summer Olympics, Wednesday, July 28, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Daniil Medvedev, of the Russian Olympic Committee, pauses during a third round men's tennis match against Fabio Fognini, of Italy, at the 2020 Summer Olympics, Wednesday, July 28, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Belinda Bencic, of Switzerland, reacts after defeating Anastasia Pavlyuchenkova, of the Russian Olympic Committee, in the quarterfinal round of the women's tennis competition at the 2020 Summer Olympics, Wednesday, July 28, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Paula Badosa, of Spain, is helped off the court in a wheelchair after retiring due to illness during the quarterfinals of the tennis competition at the 2020 Summer Olympics, Wednesday, July 28, 2021, in Tokyo, Japan. (AP Photo/Seth Wenig)

Pablo Carreno Busta, of Spain, tries to keep cool between games against Dominik Koepfer, of Germany, during the third round of the tennis competition at the 2020 Summer Olympics, Wednesday, July 28, 2021, in Tokyo, Japan. (AP Photo/Seth Wenig)

Daniil Medvedev, of the Russian Olympic Committee, is tended to during a third round men's tennis match against Fabio Fognini, of Italy, at the 2020 Summer Olympics, Wednesday, July 28, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Fabio Fognini, of Italy, throws his racket during a third round men's tennis match against Daniil Medvedev, of the Russian Olympic Committee, at the 2020 Summer Olympics, Wednesday, July 28, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Novak Djokovic, of Serbia, returns to Alejandro Davidovich Fokina, of Spain, during the third round of the men's tennis competition at the 2020 Summer Olympics, Wednesday, July 28, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Elina Svitolina, of the Ukraine, plays Camila Giorgi, of Italy, during the quarterfinals of the tennis competition at the 2020 Summer Olympics, Wednesday, July 28, 2021, in Tokyo, Japan. (AP Photo/Seth Wenig)

The Australian doubles team of Ashleigh Barty, right, and Storm Sanders talk during the quarterfinals of the tennis competition at the 2020 Summer Olympics, Wednesday, July 28, 2021, in Tokyo, Japan. (AP Photo/Seth Wenig)

Kei Nishikori, of Japan, plays Ilya Ivashka, of Belarus, during the third round of the tennis competition at the 2020 Summer Olympics, Wednesday, July 28, 2021, in Tokyo, Japan. (AP Photo/Seth Wenig)