Serbia’s Novak Djokovic reached the Olympic singles quarter-finals for a record fourth time by beating Germany’s Dominic Koepfer 7-5 6-3 on Wednesday but looked in the mood to go much deeper in the tournament.
For all his 24 Grand Slam titles and countless other accolades, the Olympics has never been especially kind to the 37-year-old for whom a bronze medal remains his only souvenir.…