Novak Djokovic continued his bid for a record 25th Grand Slam title in style as he stormed past qualifier Jan-Lennard Struff to qualify for the US Open quarter-finals.
Despite twice receiving medical attention, the Serb rarely looked troubled as he raced to a dominant 6-3 6-3 6-2 victory in under two hours.
While the win was further evidence of Djokovic’s pedigree, questions still remain over the 38-year-old’s physical condition.
Again, there were signs of wear and tear as he called for the physio to treat a neck issue and then a problem with his right forearm against German Struff.
However, the setbacks did not appear to harm his tennis as he dictated play with relentless hitting – firing 33 winners and 12 aces, with no double faults.
The world number seven highlighted his serve for keeping him out of trouble on Arthur Ashe Stadium.
“It definitely helps if you serve well. I think I had a great serving performance in the last round and also tonight,” Djokovic said.
“I just saw the stats, I out-served one of the guys that had the most aces during the tournament this year, so that’s a great stat.
“Obviously that helps make my life easier on the court. Maybe I don’t need to work as hard or unnecessarily more than I have to.”
Djokovic will face American hope Taylor Fritz in the last eight.