Playing his best tennis of the year when he needed it most , Isner survived the three - set encounter , winning one more point than Sock , 106 to 105 .
John Isner defeated fellow American Jack Sock in an ATP World Tour Masters 1000 quarterfinal match .
Playing John Isner 's best tennis of the year when he needed it most , John Isner survived the three - set encounter , winning one more point than Sock , 106 to 105 .
John Isner defeated fellow American Jack Sock in an ATP World Tour Masters 1000 quarterfinal match .