Rafael Nadal of Spain celebrates after defeating Janko Tipsarevic of Serbia during their match on day 5 of the ATP 500 World Tour Barcelona Open Banco Sabadell 2012 tennis tournament at the Real Club de Tenis on April 27, 2012 in Barcelona, Spain
Winner Serbia's Novak Djokovic (L) and runner-up Switzerland's Roger Federer hold their trophies during the presentation at the end of their men's singles final match on day thirteen of the 2014 Wimbledon Championships at The All England Tennis Club in Wimbledon, southwest London, on July 6, 2014
Belarus's Victoria Azarenka plays a return during her women's singles match against Romania's Monica Niculescu on the second day of the Australian Open tennis tournament in Melbourne on January 15, 2013.
Spain's Rafael Nadal plays a shot during his first round men's singles match against Brazil's Thomaz Bellucci on the second day of the 2012 Wimbledon Championships tennis tournament at the All England Tennis Club in Wimbledon, southwest London, on June 26, 2012
Caroline Wozniacki of Denmark plays a forehand in her singles final match against Venus Williams of USA during day six of the 2015 ASB Classic at ASB Tennis Centre on January 10, 2015 in Auckland, New Zealand