Spain's Rafael Nadal returns against Serbia's Novak Djokovic in their semifinal match at the French Open tennis tournament, at Roland Garros stadium in Paris, Friday June 7, 2013. (AP Photo/Christophe Ena)

Photo by: Christophe Ena

Spain's Rafael Nadal returns against Serbia's Novak Djokovic in their semifinal match at the French Open tennis tournament, at Roland Garros stadium in Paris, Friday June 7, 2013. (AP Photo/Christophe Ena)