KEY BISCAYNE, FL - MARCH 26: Kei Nishikori of Japan serves to Pierre-Hugues Herbert of France during the Miami Open presented by Itau at Crandon Park Tennis Center on March 26, 2016 in Key Biscayne, Florida. (Photo by Matthew Stockman/Getty Images)
KEY BISCAYNE, FL - MARCH 26: Kei Nishikori of Japan serves to Pierre-Hugues Herbert of France during the Miami Open presented by Itau at Crandon Park Tennis Center on March 26, 2016 in Key Biscayne, Florida. (Photo by Matthew Stockman/Getty Images)