Del Potro, heat get best of Isner in quarterfinals Juan Martin del Potro beat John Isner 6-7 (5), 6-3, 7-6 (4), 6-2 on a 90-degree day to make a second straight US Open semifinal and extend the Americans’ drought at their host tournament. Author: sportallinfo Published: 5 settembre 2018 Categories: Other Sports