New York, Sept. 1 -- Serbia's tennis maestro Novak Djokovic directed a clean and swift performance to show Germany's Jan-Lennard Struff the exit route and set up a quarter-final showdown with number four seed and home favourite Taylor Fritz at the US Open.

The 38-year-old Djokovic became the oldest man in history to qualify for all four major singles quarter-finals in one season, following his 6-3, 6-3, 6-2 victory over the German in a contest that lasted for an hour and 49 minutes. He also joined Pancho Gonzalez, Ken Rosewall and Jimmy Connors to become the fourth-oldest to advance to the US Open quarter-finals.

After enduring a thorny start to the tournament where Djokovic battled fitness concerns and tricky on-court tests at Flushing...