Spain's Rafael Nadal returns against Switzerland's Stanislas Wawrinka in their quarterfinal match at the French Open tennis tournament, at Roland Garros stadium in Paris, Wednesday June 5, 2013. (AP Photo/Petr David Josek)

Photo by: Petr David Josek

Spain's Rafael Nadal returns against Switzerland's Stanislas Wawrinka in their quarterfinal match at the French Open tennis tournament, at Roland Garros stadium in Paris, Wednesday June 5, 2013. (AP Photo/Petr David Josek)