Rafael Nadal of Spain celebrates after defeating Kei Nishikori of Japan during their fourth round match at the Australian Open tennis championship in Melbourne, Australia, Monday, Jan. 20, 2014.(AP Photo/Eugene Hoshiko)
Rafael Nadal of Spain celebrates after defeating Kei Nishikori of Japan during their fourth round match at the Australian Open tennis championship in Melbourne, Australia, Monday, Jan. 20, 2014.(AP Photo/Aaron Favila)
Rafael Nadal of Spain celebrates after his win over Kei Nishikori of Japan during their fourth round match at the Australian Open tennis championship in Melbourne, Australia, Monday, Jan. 20, 2014.(AP Photo/Eugene Hoshiko)
Rafael Nadal of Spain dries himself with a towel during his fourth round match against Kei Nishikori of Japan at the Australian Open tennis championship in Melbourne, Australia, Monday, Jan. 20, 2014.(AP Photo/Aaron Favila)