Russia's Daria Kasatkina celebrates after defeating Jil Teichmann during their Billie Jean King Cup final tennis match in Prague, Czech Republic, Saturday, Nov. 6, 2021. (AP Photo/Petr David Josek)

Russia's Daria Kasatkina celebrates after defeating Jil Teichmann during their Billie Jean King Cup final tennis match in Prague, Czech Republic, Saturday, Nov. 6, 2021. (AP Photo/Petr David Josek)

Russia's Daria Kasatkina celebrates after defeating Switzerland's Jil Teichmann during their Billie Jean King Cup final tennis match in Prague, Czech Republic, Saturday, Nov. 6, 2021. (AP Photo/Petr David Josek)

Russia's Daria Kasatkina serves to Switzerland's Jil Teichmann during their Billie Jean King Cup final tennis match in Prague, Czech Republic, Saturday, Nov. 6, 2021. (AP Photo/Petr David Josek)

Russia's Daria Kasatkina celebrates after winning a point against Switzerland's Jil Teichmann during their Billie Jean King Cup final tennis match in Prague, Czech Republic, Saturday, Nov. 6, 2021. (AP Photo/Petr David Josek)

Switzerland's Jil Teichmann returns a ball to Russia's Daria Kasatkina during their Billie Jean King Cup final tennis match in Prague, Czech Republic, Saturday, Nov. 6, 2021. (AP Photo/Petr David Josek)

Switzerland's Jil Teichmann serves a ball to Russia's Daria Kasatkina during their Billie Jean King Cup final tennis match in Prague, Czech Republic, Saturday, Nov. 6, 2021. (AP Photo/Petr David Josek)

Switzerland's Jil Teichmann serves to Russia's Daria Kasatkina during their Billie Jean King Cup final tennis match in Prague, Czech Republic, Saturday, Nov. 6, 2021. (AP Photo/Petr David Josek)

Russia's Daria Kasatkina returns a ball to Switzerland's Jil Teichmann during their Billie Jean King Cup final tennis match in Prague, Czech Republic, Saturday, Nov. 6, 2021. (AP Photo/Petr David Josek)

Switzerland's Jil Teichmann returns a ball to Russia's Daria Kasatkina during their Billie Jean King Cup final tennis match in Prague, Czech Republic, Saturday, Nov. 6, 2021. (AP Photo/Petr David Josek)