Tennis - Australian Open - Men's Singles Final - Melbourne Park, Melbourne, Australia, February 21, 2021 Tournament winner Novak Djokovic of Serbia and runner up Daniil Medvedev of Russia pose for a photo holding their trophies after their final match REUTERS/Kelly Defina

Tennis - Australian Open - Men's Singles Final - Melbourne Park, Melbourne, Australia, February 21, 2021 Tournament winner Novak Djokovic of Serbia and runner up Daniil Medvedev of Russia pose for a photo holding their trophies after their final match REUTERS/Asanka Brendon Ratnayake

Tennis - Australian Open - Men's Singles Final - Melbourne Park, Melbourne, Australia, February 21, 2021 Tournament winner Novak Djokovic of Serbia and runner up Daniil Medvedev of Russia holding their trophies after their final match REUTERS/Asanka Brendon Ratnayake

Tennis - Australian Open - Men's Singles Final - Melbourne Park, Melbourne, Australia, February 21, 2021 Tournament winner Novak Djokovic of Serbia and runner up Daniil Medvedev of Russia speak whilst holding their trophies after their final match REUTERS/Kelly Defina

Tennis - Australian Open - Men's Singles Final - Melbourne Park, Melbourne, Australia, February 21, 2021 Runner up Daniil Medvedev of Russia and tournament winner Novak Djokovic of Serbia pose for a photo with their trophies after their final match. Crowds are at a reduced capacity for this years event following the outbreak of the coronavirus disease (COVID-19) REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Final - Melbourne Park, Melbourne, Australia, February 21, 2021 Tournament winner Novak Djokovic of Serbia and runner up Daniil Medvedev of Russia pose for a photo with their trophies after their final match. Crowds are at a reduced capacity for this years event following the outbreak of the coronavirus disease (COVID-19) REUTERS/Jaimi Joy

Japan's Naomi Osaka competes against Jennifer Brady of the U.S. in their women's singles final match during the Australian Open tennis tournament at Melbourne Park in Melbourne, Australia, February 20, 2021. Picture taken February 20, 2021. REUTERS/Loren Elliott

Japan's Naomi Osaka embraces Jennifer Brady of the U.S. after winning their women's singles final match during the Australian Open tennis tournament at Melbourne Park in Melbourne, Australia, February 20, 2021. Picture taken February 20, 2021. REUTERS/Loren Elliott

Japan's Naomi Osaka looks up at the people in her player box while celebrating after defeating Jennifer Brady of the U.S. in their women's singles final match during the Australian Open tennis tournament at Melbourne Park in Melbourne, Australia, February 20, 2021. Picture taken February 20, 2021. REUTERS/Loren Elliott

Japan's Naomi Osaka heads back toward the court after celebrating with the people in her player box following her victory over Jennifer Brady of the U.S. in their women's singles final match during the Australian Open tennis tournament at Melbourne Park in Melbourne, Australia, February 20, 2021. Picture taken February 20, 2021. REUTERS/Loren Elliott

Japan's Naomi Osaka is pictured with the trophy following her victory over Jennifer Brady of the U.S. in their women's singles final match during the Australian Open tennis tournament at Melbourne Park in Melbourne, Australia, February 20, 2021. Picture taken February 20, 2021. REUTERS/Loren Elliott

Japan's Naomi Osaka celebrates after defeating Jennifer Brady of the U.S. in their women's singles final match during the Australian Open tennis tournament at Melbourne Park in Melbourne, Australia, February 20, 2021. Picture taken February 20, 2021. REUTERS/Loren Elliott

Gloved men carry the men's and women's singles championship trophies in advance of the Australian Open tennis tournament final matches at Melbourne Park in Melbourne, Australia, February 20, 2021. REUTERS/Loren Elliott

Gloved men carry the men's and women's singles championship trophies in advance of the Australian Open tennis tournament final matches at Melbourne Park in Melbourne, Australia, February 20, 2021. REUTERS/Loren Elliott

Serena Williams of the U.S. during her semi final match against Japan's Naomi Osaka in the Australian Open tennis tournament at Melbourne Park in Melbourne, Australia, February 18, 2021. Picture taken February 18, 2021. REUTERS/Loren Elliott

Serena Williams of the U.S. during her semi final match against Japan's Naomi Osaka in the Australian Open tennis tournament at Melbourne Park in Melbourne, Australia, February 18, 2021. Picture taken February 18, 2021. REUTERS/Loren Elliott

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 17, 2021 Spain's Rafael Nadal in action during his quarter final match against Greece's Stefanos Tsitsipas. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Jaimi Joy

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 17, 2021 Spain's Rafael Nadal in action during his quarter final match against Greece's Stefanos Tsitsipas. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Loren Elliott

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 17, 2021 Spain's Rafael Nadal is seen on a big screen during his quarter final match against Greece's Stefanos Tsitsipas. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Loren Elliott

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 17, 2021 General view of photographers wearing protective masks as Greece's Stefanos Tsitsipas in action during his quarter final match against Spain's Rafael Nadal. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Jaimi Joy

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 17, 2021 General view of Spain's Rafael Nadal in action during his quarter final match against Greece's Stefanos Tsitsipas . The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Loren Elliott

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 17, 2021 General view of Spain's Rafael Nadal in action during his quarter final match against Greece's Stefanos Tsitsipas . The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Loren Elliott

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 17, 2021 General view of the large screen showing Spain's Rafael Nadal in action during his quarter final match against Greece's Stefanos Tsitsipas. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Loren Elliott

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 17, 2021 General view of Greece's Stefanos Tsitsipas in action during his quarter final match against Spain's Rafael Nadal. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Loren Elliott

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 17, 2021 Australia's Ashleigh Barty in action during her quarter final match against Czech Republic's Karolína Muchova. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Kelly Defina

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 17, 2021 Australia's Ashleigh Barty in action during her quarter final match against Czech Republic's Karolína Muchova. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Kelly Defina

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 17, 2021 Australia's Ashleigh Barty in action during her quarter final match against Czech Republic's Karolína Muchova. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Kelly Defina

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 17, 2021 Australia's Ashleigh Barty in action during her quarter final match against Czech Republic's Karolína Muchova. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Kelly Defina

Serena Williams of the U.S. during her quarter final match against Romania's Simona Halep in the Australian Open tennis tournament at Melbourne Park in Melbourne, Australia, February 16, 2021. Picture taken February 16, 2021. REUTERS/Loren Elliott

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 17, 2021 General view as a reflection of an image of Serbia's Novak Djokovic is seen. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19)

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 17, 2021 General view as a reflection of an image of Germany's Alexander Zverev is seen. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Loren Elliott

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 16, 2021 Serbia's Novak Djokovic reacts during his quarter final match against Germany's Alexander Zverev. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Asanka Brendon Ratnayake

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 16, 2021 General view of Serbia's Novak Djokovic in action during his quarter final match against Germany's Alexander Zverev. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Loren Elliott

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 16, 2021 General view of Serbia's Novak Djokovic in action during his quarter final match against Germany's Alexander Zverev. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Loren Elliott

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 16, 2021 General view of Serena Williams of the U.S. in action during her quarter final match against Romania's Simona Halep. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Jaimi Joy

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 16, 2021 General view of Serena Williams of the U.S. in action during her quarter final match against Romania's Simona Halep. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Jaimi Joy

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 16, 2021 General view of Serena Williams of the U.S. in action during her quarter final match against Romania's Simona Halep. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Jaimi Joy

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 16, 2021 Staff member wearing a protective face mask is seen during the quarter final match between Russia's Aslan Karatsev and Bulgaria's Grigor Dimitrov. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Kelly Defina

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 16, 2021 General view during the quarter final match between Bulgaria's Grigor Dimitrov and Russia's Aslan Karatsev. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Jaimi Joy

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 15, 2021 General view during the fourth round match between Czech Republic's Karolina Muchova and Belgium's Elise Mertens. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19). Picture taken February 15, 2021 REUTERS/Jaimi Joy

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 15, 2021 General view during the fourth round match between Czech Republic's Karolina Muchova and Belgium's Elise Mertens. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19). Picture taken February 15, 2021 REUTERS/Jaimi Joy

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 16, 2021 General view of photographers during the quarter final match between Japan's Naomi Osaka and Taiwan's Su-Wei Hsieh. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Loren Elliott

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 15, 2021 General view of Czech Republic's Karolina Muchova in action during her fourth round match against Belgium's Elise Mertens. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Jaimi Joy

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 15, 2021 General view of an empty court after Italy's Matteo Berrettini withdraws from his fourth round match against Greece's Stefanos Tsitsipas. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Jaimi Joy

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 15, 2021 General view during the fourth round match between Australia’s Ashleigh Barty and Shelby Rogers of the U.S. .The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Loren Elliott

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 15, 2021 Australia’s Ashleigh Barty in action during her fourth round match against Shelby Rogers of the U.S. .The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Kelly Defina

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 15, 2021 General view of Spain's Rafael Nadal during his fourth round match against Italy's Fabio Fognini. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Loren Elliott

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 15, 2021 General view of Spain's Rafael Nadal during his fourth round match against Italy's Fabio Fognini. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Loren Elliott

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 15, 2021 General view of Spain's Rafael Nadal during his fourth round match against Italy's Fabio Fognini. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Loren Elliott

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 15, 2021 General view of Italy's Fabio Fognini during his fourth round match against Spain's Rafael Nadal. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Loren Elliott

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 15, 2021 General view of Spain's Rafael Nadal during his fourth round match against Italy's Fabio Fognini. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Loren Elliott

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 15, 2021 General view of Spain's Rafael Nadal during his fourth round match against Italy's Fabio Fognini. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Loren Elliott

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 15, 2021 General view of the fourth round match between Jennifer Brady of the U.S. and Croatia's Donna Vekic. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Loren Elliott

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 15, 2021 General view of Ukraine's Elina Svitolina during her fourth round match against Jessica Pegula of the U.S.. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Asanka Brendon Ratnayake

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 15, 2021 General view of the fourth round match between Croatia's Donna Vekic and Jennifer Brady of the U.S.. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Kelly Defina

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 15, 2021 General view of the fourth round match between Croatia's Donna Vekic and Jennifer Brady of the U.S.. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Kelly Defina

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 15, 2021 General view of the fourth round match between Croatia's Donna Vekic and Jennifer Brady of the U.S.. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Kelly Defina

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 15, 2021 General view during the fourth round match between Jessica Pegula of the U.S. and Ukraine's Elina Svitolina. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Asanka Brendon Ratnayake

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 15, 2021 General view during the fourth round match between Jessica Pegula of the U.S. and Ukraine's Elina Svitolina. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Asanka Brendon Ratnayake

Tennis - Australian Open - Melbourne Park, Melbourne, Australia, February 15, 2021 General view of the stands during the fourth round match between Jessica Pegula of the U.S. and Ukraine's Elina Svitolina. The tournament continues without crowds after the state of Victoria was placed under a snap lockdown from Friday to contain a fresh outbreak of the coronavirus disease (COVID-19) REUTERS/Asanka Brendon Ratnayake