Garbiñe Muguruza, of Spain, reacts during the final match against Anett Kontaveit, of Estonia, of the WTA Finals tennis tournament in Guadalajara, Mexico, Wednesday, Nov. 17, 2021. (AP Photo/Refugio Ruiz)

Anett Kontaveit, of Estonia, poses with her trophy after being defeated by Garbiñe Muguruza, of Spain, during the final match of the WTA Finals tennis tournament in Guadalajara, Mexico, Wednesday, Nov. 17, 2021. (AP Photo/Refugio Ruiz)

Garbiñe Muguruza, of Spain, holds the trophy during an awarding ceremony after defeating Anett Kontaveit, of Estonia, at the final match of the WTA Finals tennis tournament in Guadalajara, Mexico, Wednesday, Nov. 17, 2021. (AP Photo/Refugio Ruiz)

Garbiñe Muguruza, of Spain, returns a shot to Anett Kontaveit, of Estonia, during the final match of the WTA Finals tennis tournament in Guadalajara, Mexico, Wednesday, Nov. 17, 2021. (AP Photo/Refugio Ruiz)

Garbiñe Muguruza, of Spain, holds the trophy during an awarding ceremony after defeating Anett Kontaveit, of Estonia, at the final match of the WTA Finals tennis tournament in Guadalajara, Mexico, Wednesday, Nov. 17, 2021. (AP Photo/Refugio Ruiz)

Anett Kontaveit, of Estonia, returns a shot to Garbiñe Muguruza, of Spain, during the final match of the WTA Finals tennis tournament in Guadalajara, Mexico, Wednesday, Nov. 17, 2021. (AP Photo/Refugio Ruiz)

Garbiñe Muguruza, of Spain, center, holds the trophy accompanied by former tennis players Billie Jean King, right, Conchita Martinez, second from right, Chris Evert, left, and Martina Navratilova, after defeating Anett Kontaveit, of Estonia, at the final match of the WTA Finals tennis tournament in Guadalajara, Mexico, Wednesday, Nov. 17, 2021. (AP Photo/Refugio Ruiz)

Garbiñe Muguruza, of Spain, reacts after defeating Anett Kontaveit, of Estonia, during the final match of the WTA Finals tennis tournament in Guadalajara, Mexico, Wednesday, Nov. 17, 2021. (AP Photo/Refugio Ruiz)

Anett Kontaveit, of Estonia, reacts during the final match against Garbiñe Muguruza, of Spain, of the WTA Finals tennis tournament in Guadalajara, Mexico, Wednesday, Nov. 17, 2021. (AP Photo/Refugio Ruiz)

Garbiñe Muguruza, of Spain, center, holds the trophy accompanied by former tennis players Billie Jean King, right, and Chris Evert after defeating Anett Kontaveit, of Estonia, at the final match of the WTA Finals tennis tournament in Guadalajara, Mexico, Wednesday, Nov. 17, 2021. (AP Photo/Refugio Ruiz)

Garbiñe Muguruza, of Spain, reacts after defeating Anett Kontaveit, of Estonia, during the final match of the WTA Finals tennis tournament in Guadalajara, Mexico, Wednesday, Nov. 17, 2021. (AP Photo/Refugio Ruiz)

Garbiñe Muguruza, of Spain, holds the trophy during an awarding ceremony after defeating Anett Kontaveit, of Estonia, at the final match of the WTA Finals tennis tournament in Guadalajara, Mexico, Wednesday, Nov. 17, 2021. (AP Photo/Refugio Ruiz)