Kei Nishikori of Japan, returns a shot from Roger Federer of Switzerland, at the Sony Open Tennis tournament, Wednesday, March 26, 2014 in Key Biscayne, Fla. (AP Photo/Wilfredo Lee)

Roger Federer, Kei Nishikori

Kei Nishikori of Japan, returns a shot from Roger Federer of Switzerland, at the Sony Open Tennis tournament, Wednesday, March 26, 2014 in Key Biscayne, Fla. (AP Photo/Wilfredo Lee)

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