LONDON, ENGLAND - JULY 08: (L-R) Novak Djokovic and Jelena Ristic attends the Novak Djokovic Foundation London gala dinner at The Roundhouse on July 8, 2013 in London, England. (Photo by Ben A. Pruchnie/Getty Images for Novak Djokovic Foundation)
LONDON, ENGLAND - JULY 08: (L-R) Novak Djokovic and Jelena Ristic attends the Novak Djokovic Foundation London gala dinner at The Roundhouse on July 8, 2013 in London, England. (Photo by Ben A. Pruchnie/Getty Images for Novak Djokovic Foundation)