While practicing his serve on Louis Armstrong arena, Novak Djokovic heard somebody shouting : “Djokovic, will you marry me? ” . Turned out to be a child, and Novak being amused (as well as the spectators) invited the child on the court , gave him his racquet and asked him to practice a few serves – which the boy did, quite well I would say. Everybody had fun as you can see from attached images.