The world's oldest tennis player Ukrainian Leonid Stanislavskyi, 97, practices on court in Kharkiv, Ukraine July 7, 2021.A Guinness World Record holder as the world's oldest tennis player, Stanislavskyi has been training hard ahead of the 2021 Super-Seniors World Championship due to be held in October in Mallorca, Spain. REUTERS/Vyacheslav Madiyevskyy

The world's oldest tennis player Ukrainian Leonid Stanislavskyi, 97, practices on court in Kharkiv, Ukraine July 7, 2021. For the first time, the International Tennis Federation has introduced a 90-and-over age group in the 2021 tournament after Stanislavskyi sent a written request to the federation asking for the new category to be added. REUTERS/Vyacheslav Madiyevskyy

The world's oldest tennis player Ukrainian Leonid Stanislavskyi, 97, practices on court in Kharkiv, Ukraine July 7, 2021. Stanislavskyi said the secret to his longevity was a mixture of good genes and regular sport. REUTERS/Vyacheslav Madiyevskyy

The world's oldest tennis player Ukrainian Leonid Stanislavskyi, 97, walks on court before an award ceremony of the Guinness World Record certificate in Kharkiv, Ukraine July 7, 2021. REUTERS/Vyacheslav Madiyevskyy

The world's oldest tennis player Ukrainian Leonid Stanislavskyi, 97, takes part in an award ceremony of the Guinness World Record certificate in Kharkiv, Ukraine July 7, 2021. REUTERS/Vyacheslav Madiyevskyy

The world's oldest tennis player Ukrainian Leonid Stanislavskyi, 97, takes part in an award ceremony of the Guinness World Record certificate in Kharkiv, Ukraine July 7, 2021. REUTERS/Vyacheslav Madiyevskyy