United States' Serena Williams celebrates after defeating Romania's Simona Halep during their quarterfinal match at the Australian Open tennis championship in Melbourne, Australia, Tuesday, Feb. 16, 2021.(AP Photo/Hamish Blair)

United States' Jennifer Brady serves to compatriot Jessica Pegula during their quarterfinal match at the Australian Open tennis championship in Melbourne, Australia, Wednesday, Feb. 17, 2021.(AP Photo/Andy Brownbill)

United States' Jennifer Brady, right, is embraced by compatriot Jessica Pegula after winning their quarterfinal match at the Australian Open tennis championship in Melbourne, Australia, Wednesday, Feb. 17, 2021.(AP Photo/Andy Brownbill)

United States' Sofia Kenin waves as she leaves the court following her second round loss to Estonia's Kaia Kanepi during at the Australian Open tennis championship in Melbourne, Australia, Thursday, Feb. 11, 2021.(AP Photo/Rick Rycroft)