Naomi Osaka, of Japan, reacts after losing a point to Marketa Vondrousova, of the Czech Republic, during the third round of the tennis competition at the 2020 Summer Olympics, Tuesday, July 27, 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)

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)

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)