United States' Venus Williams rests in her chair during break in her match against Petra Kvitova of the Czech Republic in a tuneup tournament ahead of the Australian Open tennis championships in Melbourne, Australia, Tuesday, Feb. 2, 2021. (AP Photo/Andrew Brownbill)

Serbia's Novak Djokovic celebrates after defeating Canada's Denis Shapovalov in their ATP Cup match in Melbourne, Australia, Tuesday, Feb. 2, 2021. (AP Photo/Hamish Blair)

Spain's Rafael Nadal makes a backhand return to Austria's Dominic Thiem during an exhibition tennis event in Adelaide, Australia, Friday, Jan 29. 2021. (Kelly Barnes/AAP Image via AP)

United States' Sofia Kenin waits to receive serve from Italy's Camila Giorgi during their match at a tuneup tournament ahead of the Australian Open tennis championships in Melbourne, Australia, Tuesday, Feb. 2, 2021. (AP Photo/Andrew Brownbill)

Japan's Naomi Osaka serves to France's Alize Cornet during a tuneup tournament ahead of the Australian Open tennis championships in Melbourne, Australia, Tuesday, Feb. 2, 2021. (AP Photo/Andrew Brownbill)

Canada's Denis Shapovalov makes a forehand return to Serbia's Novak Djokovic during their ATP Cup match in Melbourne, Australia, Tuesday, Feb. 2, 2021. (AP Photo/Hamish Blair)

Australia's Ash Barty reacts after defeating Romania's Ana Bogdan in their match during a tuneup tournament ahead of the Australian Open tennis championships in Melbourne, Australia, Tuesday, Feb. 2, 2021. (AP Photo/Andrew Brownbill)

FILE - In this March 21, 2019 file photo, Bianca Andreescu, of Canada, left, talks with her coach Sylvain Bruneau during her match against Irina Camelia Begu, of Romania, at the Miami Open tennis tournament in Miami Gardens, Fla. Bruneau has released a statement, Sunday, Jan. 17, 2021, saying he was the positive coronavirus case aboard the flight from Abu Dhabi to Melbourne and he had followed all protocols and procedures, including producing a negative test within 72 hours before the flight departure and has "no idea how I might have contracted the virus." (AP Photo/Lynne Sladky, File)

United States' Tennys Sandgren falls during his match against Australia's John-Patrick Smith at a tuneup tournament ahead of the Australian Open tennis championships in Melbourne, Australia, Tuesday, Feb. 2, 2021. (AP Photo/Andrew Brownbill)

Australia's Nick Kyrgios reacts during a break in his match against France's Alexandre Muller at a tuneup tournament ahead of the Australian Open tennis championships in Melbourne, Australia, Tuesday, Feb. 2, 2021. (AP Photo/Andrew Brownbill)

Petra Kvitova of the Czech Republic serves to United States' Venus Williams during a tuneup tournament ahead of the Australian Open tennis championships in Melbourne, Australia, Tuesday, Feb. 2, 2021. (AP Photo/Andrew Brownbill)