TOPSHOT - Serbian tennis player Novak Djokovic returns the ball to German tennis player Alexander Zverev during their single match at the Adria Tour, Novak Djokovic's Balkans charity tennis tournament in Belgrade on June 14, 2020. - The ATP and WTA Tours have been suspended since March due to the COVID-19 pandemic and will not resume at least until the end of July 2020. (Photo by ANDREJ ISAKOVIC / AFP)