INDIAN WELLS, CA - MARCH 17: Kei Nishikori of Japan walks off the court after his three set defeat by Jack Sock of the United States in in their quarter final match during day twelve of the BNP Paribas Open at Indian Wells Tennis Garden on March 17, 2017 in Indian Wells, California. (Photo by Clive Brunskill/Getty Images)

INDIAN WELLS, CA - MARCH 17: Kei Nishikori of Japan walks off the court after his three set defeat by Jack Sock of the United States in in their quarter final match during day twelve of the BNP Paribas Open at Indian Wells Tennis Garden on March 17, 2017 in Indian Wells, California. (Photo by Clive Brunskill/Getty Images)