Donna Vekic, of Croatia, returns to Aryna Sabalenka, of Belarus, during second round of the tennis competition at the 2020 Summer Olympics, Monday, July 26, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Aryna Sabalenka, of Belarus, returns to Donna Vekic, of Croatia, during second round of the tennis competition at the 2020 Summer Olympics, Monday, July 26, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Aryna Sabalenka, of Belarus, returns to Donna Vekic, of Croatia, during second round of the tennis competition at the 2020 Summer Olympics, Monday, July 26, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Donna Vekic, of Croatia, returns to Aryna Sabalenka, of Belarus, during second round of the tennis competition at the 2020 Summer Olympics, Monday, July 26, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Donna Vekic, of Croatia, returns to Aryna Sabalenka, of Belarus, during second round of the tennis competition at the 2020 Summer Olympics, Monday, July 26, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Donna Vekic, of Croatia, returns to Aryna Sabalenka, of Belarus, during second round of the tennis competition at the 2020 Summer Olympics, Monday, July 26, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Donna Vekic, of Croatia, returns to Aryna Sabalenka, of Belarus, during second round of the tennis competition at the 2020 Summer Olympics, Monday, July 26, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Aryna Sabalenka, of Belarus, returns to Donna Vekic, of Croatia, during second round of the tennis competition at the 2020 Summer Olympics, Monday, July 26, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Aryna Sabalenka, of Belarus, serves to Donna Vekic, of Croatia, during second round of the tennis competition at the 2020 Summer Olympics, Monday, July 26, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Donna Vekic, of Croatia, returns to Aryna Sabalenka, of Belarus, during second round of the tennis competition at the 2020 Summer Olympics, Monday, July 26, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Donna Vekic, of Croatia, reacts after defeating Aryna Sabalenka, of Belarus, during second round of the tennis competition at the 2020 Summer Olympics, Monday, July 26, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Donna Vekic, of Croatia, reacts after defeating Aryna Sabalenka, of Belarus, during second round of the tennis competition at the 2020 Summer Olympics, Monday, July 26, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Donna Vekic, of Croatia, returns to Aryna Sabalenka, of Belarus, during second round of the tennis competition at the 2020 Summer Olympics, Monday, July 26, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)

Donna Vekic, of Croatia, reacts after defeating Aryna Sabalenka, of Belarus, during second round of the tennis competition at the 2020 Summer Olympics, Monday, July 26, 2021, in Tokyo, Japan. (AP Photo/Patrick Semansky)