Ukraine's Elina Svitolina makes a forehand return to United States' Coco Gauff during their second round match at the Australian Open tennis championship in Melbourne, Australia, Thursday, Feb. 11, 2021.(AP Photo/Rick Rycroft)

Spain's Rafael Nadal celebrates after defeating United States' Michael Mmoh during their second round match at the Australian Open tennis championship in Melbourne, Australia, Thursday, Feb. 11, 2021.(AP Photo/Rick Rycroft)

Italy's Fabio Fognini, right, speaks as compatriot Salvatore Caruso walks away after their second round match at the Australian Open tennis championship in Melbourne, Australia, Thursday, Feb. 11, 2021. Fognini won the match. (AP Photo/Hamish Blair)

United States' Coco Gauff makes a backhand return to Ukraine's Elina Svitolina during their second round match at the Australian Open tennis championship in Melbourne, Australia, Thursday, Feb. 11, 2021.(AP Photo/Rick Rycroft)

Greece's Stefanos Tsitsipas gestures during his second round game against Australia's Thanasi Kokkinakis at the Australian Open tennis championship in Melbourne, Australia, Thursday, Feb. 11, 2021.(AP Photo/Rick Rycroft)

Australia's Thanasi Kokkinakis celebrates after winning the fourth set against Greece's Stefanos Tsitsipas during their second round match at the Australian Open tennis championship in Melbourne, Australia, Thursday, Feb. 11, 2021.(AP Photo/Rick Rycroft)

United States' Mackenzie McDonald makes a backhand return to Croatia's Borna Coric during their second round match at the Australian Open tennis championship in Melbourne, Australia, Thursday, Feb. 11, 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)

Estonia's Kaia Kanepi waves after defeating United States' Sofia Kenin in their second round match at the Australian Open tennis championship in Melbourne, Australia, Thursday, Feb. 11, 2021.(AP Photo/Rick Rycroft)

Australia's Ash Barty makes a forehand return to compatriot Daria Gavrilova during their second round match at the Australian Open tennis championship in Melbourne, Australia, Thursday, Feb. 11, 2021.(AP Photo/Rick Rycroft)