Novak Djokovic hit top form at the US Open to set up a quarter-final clash with Taylor Fritz.
Djokovic had battled his way through to the fourth round, negotiating physical discomfort and some uncharacteristic wobbles, but he brushed aside qualifier Jan-Lennard Struff 6-3 6-3 6-2 in just an hour and 49 minutes under the lights on Arthur Ashe Stadium.
