INDIAN WELLS, CA - MARCH 18: Jack Sock return a shot to Roger Federer of Switzerland during the semifinals of the BNP Paribas Open at the Indian Wells Tennis Garden on March 18, 2017 in Indian Wells, California. (Photo by Matthew Stockman/Getty Images)

INDIAN WELLS, CA - MARCH 18:  Jack Sock return a shot to Roger Federer of Switzerland during the semifinals of the BNP Paribas Open at the Indian Wells Tennis Garden on March 18, 2017 in Indian Wells, California.  (Photo by Matthew Stockman/Getty Images)