Youths play table tennis in an outdoor leisure area, amid the coronavirus disease (COVID-19) outbreak, in Ronda, southern Spain February 25, 2021. REUTERS/Jon Nazca

A healthcare worker using a table tennis paddle signals she is ready to vaccinate another patient at a coronavirus disease (COVID-19) community vaccination event, as West Virginia's vaccination rate ranks among highest in world, in Martinsburg, U.S. February 25, 2021. REUTERS/Kevin Lamarque

A healthcare worker using a table tennis paddle signals she is ready to check-in another patient at a coronavirus disease (COVID-19) community vaccination event, as West Virginia's vaccination rate ranks among highest in world, in Martinsburg, U.S. February 25, 2021. REUTERS/Kevin Lamarque

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic signs his autograph on a pregnant woman's belly during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic talks to the media as fans are seen with Serbia's flags during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic signs his autograph on a pregnant woman's belly during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic is interviewed as he holds the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic is interviewed as he holds the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Craig Tiley, CEO of Tennis Australia talks to the media during a photo shoot as a runner is seen at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with a fan during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 The Australian Open champion Serbia's Novak Djokovic autograph is seen on a pregnant woman's belly during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Staff during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic is interviewed as he holds the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic with the trophy and a fan during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Craig Tiley, CEO of Tennis Australia talks to the media during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic signs his autograph on a pregnant woman's belly during a photo shoot at Brighton Beach REUTERS/Loren Elliott TPX IMAGES OF THE DAY

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic with the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic with the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic with the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Jaimi Joy

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott TPX IMAGES OF THE DAY

Tennis - Australian Open - Men's Singles Photo Shoot - Brighton Beach, Melbourne, Australia, February 22, 2021 Australian Open champion Serbia's Novak Djokovic poses with the trophy during a photo shoot at Brighton Beach REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Final - Melbourne Park, Melbourne, Australia, February 21, 2021 Serbia's Novak Djokovic celebrates winning his final match against Russia's Daniil Medvedev REUTERS/Asanka Brendon Ratnayake

Tennis - Australian Open - Men's Singles Final - Melbourne Park, Melbourne, Australia, February 21, 2021 Serbia's Novak Djokovic celebrates with the trophy after winning his final match against Russia's Daniil Medvedev REUTERS/Asanka Brendon Ratnayake TPX IMAGES OF THE DAY

Tennis - Australian Open - Men's Singles Final - Melbourne Park, Melbourne, Australia, February 21, 2021 Serbia's Novak Djokovic celebrates with the trophy after winning his final match against Russia's Daniil Medvedev REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Final - Melbourne Park, Melbourne, Australia, February 21, 2021 Serbia's Novak Djokovic celebrates with the trophy after winning his final match against Russia's Daniil Medvedev REUTERS/Asanka Brendon Ratnayake

Tennis - Australian Open - Men's Singles Final - Melbourne Park, Melbourne, Australia, February 21, 2021 Serbia's Novak Djokovic signs autographs after winning his final match against Russia's Daniil Medvedev REUTERS/Asanka Brendon Ratnayake

Tennis - Australian Open - Men's Singles Final - Melbourne Park, Melbourne, Australia, February 21, 2021 Serbia's Novak Djokovic speaks to the crowd holding his trophy after winning his final match against Russia's Daniil Medvedev REUTERS/Asanka Brendon Ratnayake

Tennis - Australian Open - Men's Singles Final - Melbourne Park, Melbourne, Australia, February 21, 2021 Russia's Daniil Medvedev and Serbia's Novak Djokovic meet at the net after their final match. Crowds are at a reduced capacity for this years event following the outbreak of the coronavirus disease (COVID-19) REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Final - Melbourne Park, Melbourne, Australia, February 21, 2021 General view as Serbia's Novak Djokovic celebrates winning his final match against Russia's Daniil Medvedev. Crowds are at a reduced capacity for this years event following the outbreak of the coronavirus disease (COVID-19) REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Final - Melbourne Park, Melbourne, Australia, February 21, 2021 General view as Serbia's Novak Djokovic celebrates winning his final match against Russia's Daniil Medvedev. Crowds are at a reduced capacity for this years event following the outbreak of the coronavirus disease (COVID-19) REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Final - Melbourne Park, Melbourne, Australia, February 21, 2021 Serbia's Novak Djokovic celebrates winning his final match against Russia's Daniil Medvedev REUTERS/Loren Elliott

Tennis - Australian Open - Men's Singles Final - Melbourne Park, Melbourne, Australia, February 21, 2021 Serbia's Novak Djokovic celebrates winning his final match against Russia's Daniil Medvedev REUTERS/Jaimi Joy