John Isner, of the United States, rests between sets during a match against Donald Young, of the United States, at the Sony Open tennis tournament, Saturday, March 22, 2014, in Key Biscayne, Fla. (AP Photo/Wilfredo Lee)
Ernests Gulbis, of Latvia, hits to John Isner during their quarterfinal match at the BNP Paribas Open tennis tournament on Friday, March 14, 2014, in Indian Wells, Calif. (AP Photo/Mark J. Terrill)
John Isner volleys with Ernests Gulbis, of Latvia, during their quarterfinal match at the BNP Paribas Open tennis tournament on Friday, March 14, 2014, in Indian Wells, Calif. (AP Photo/Mark J. Terrill)
Ernests Gulbis, of Latvia, hits to John Isner during their quarterfinal match at the BNP Paribas Open tennis tournament on Friday, March 14, 2014, in Indian Wells, Calif. (AP Photo/Mark J. Terrill)
John Isner reaches to return a shot to Ernests Gulbis, of Latvia, during their quarterfinal match at the BNP Paribas Open tennis tournament, Friday, March 14, 2014, in Indian Wells, Calif. (AP Photo/Mark J. Terrill)