World No . 1 Novak Djokovic will enter this year 's U.S. Open without a title since April . ( CNN ) -- Djokovic loses to big-serving American John Isner at the Cincinnati Masters on Friday . Andy Murray also exits in the quarterfinals following a defeat to Czech Tomas Berdych . TL;DR
World No . 1 Novak Djokovic will enter this year 's U.S. Open without a title since April . Djokovic loses to big-serving American John Isner at the Cincinnati Masters on Friday . Andy Murray also exits in the quarterfinals following a defeat to Czech Tomas Berdych . TL;DR