Paris. Novak Djokovic needed a bit of time to assert himself Wednesday at the Paris Olympics before taking control with a five-game run for a 7-5, 6-3 victory over Dominik Koepfer of Germany, reaching the Summer Games singles quarterfinals for the fourth time.

A gold medal is pretty much the only accomplishment of significance missing from the resume of Djokovic, a 37-year-old from Serbia who has won a record 24 Grand Slam titles and spent more weeks at No. 1 than anyone in the history of the computerized tennis rankings.

That is why Djokovic, who is the top-seeded man in Paris, has proclaimed success at these Olympics his priority for the year. His one medal so far was a bronze in 2008 in Beijing.

This time, tennis matches are being played at Roland Garros, the facility that hosts the French Open, which Djokovic has won three times. One of his triumphs in a final at Court Philippe Chatrier came in 2021 against Stefanos Tsitsipas, the Greek who will be Djokovic's opponent on Thursday.

Tsitsipas beat Sebastian Baez of Argentina 7-5, 6-1.

Against Koepfer, Djokovic was patchy in parts at the outset, not as crisp as when he got past rival Rafael Nadal in straight sets in the second round. This one was 5-all in the first set, with Koepfer ripping big forehands to manage to steer Djokovic along the baseline.

Djokovic would look up at his box, where his wife, Jelena, and their son were seated. He sometimes put his arms out and muttered -- as much to himself as to them.

But he took the last two games of the first set, eliciting chants of his two-syllable nickname from the crowd: “No-le! No-le!” When Koepfer trudged to the sideline, he chucked his racket at his bench.

Djokovic then began the second set by going up 3-0. That's when Koepfer was visited by a trainer to get treatment for a blister on his left middle finger.

Koepfer is a 30-year-old left-hander who has a sub -.500 career record, only once made it as far as the fourth round at a Grand Slam tournament, is currently ranked No. 70 and never climbed higher than No. 49.

Djokovic was wearing a gray sleeve on his right knee, which was operated on in Paris in early June after he tore the meniscus during a French Open match. Surprisingly, he participated at Wimbledon less than a month after the operation and made it all the way to the final before losing to Carlos Alcaraz.

Now Djokovic is the first man to reach the singles quarterfinals four times at the Olympics since tennis returned to the Summer Games in 1988.