MILAN, ITALY - MAY 18: Novak Djokovic teaches a child how to play tennis during the expo 2015 event at Regione Lombardia square on May 18, 2015 in Milan, Italy. (Photo by Pier Marco Tacca/Getty Images)
MILAN, ITALY - MAY 18: Novak Djokovic teaches a child how to play tennis during the expo 2015 event at Regione Lombardia square on May 18, 2015 in Milan, Italy. (Photo by Pier Marco Tacca/Getty Images)