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)
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)
Kei Nishikori of Japan, serves to Roger Federer of Switzerland, at the Sony Open Tennis tournament, Wednesday, March 26, 2014 in Key Biscayne, Fla. (AP Photo/Wilfredo Lee)
Roger Federer of Switzerland, returns a shot from Kei Nishikori of Japan, at the Sony Open Tennis tournament, Wednesday, March 26, 2014 in Key Biscayne, Fla. (AP Photo/Wilfredo Lee)
Roger Federer, of Switzerland, returns the ball to Richard Gasquet, of France, during the Sony Open tennis tournament, Tuesday, March 25, 2014, in Key Biscayne, Fla. (AP Photo/Luis M. Alvarez)