Novak Djokovic's bid for a record 25th Grand Slam title has ended at the first hurdle, as the 39-year-old Serbian four-time US Open champion was beaten by unseeded Argentine Mariano Navone on Sunday night in a gruelling five-set match lasting four hours and 36 minutes. The final score — 7-6(5), 5-7, 4-6, 6-2, 6-1 — marked the first time Djokovic had lost in the opening round at Flushing Meadows, and his earliest Grand Slam exit since the 2006 Australian Open, twenty years ago.

The match, played under the lights at the USTA Billie Jean King National Tennis Center in New York, was a painful spectacle for one of tennis's most celebrated figures. Djokovic, seeded fourth, raced to early leads of 3-0 and 4-1 in the opening set before losing it in a tiebreak. He vomited at least once into a courtside bin during the third set, was treated for cramp, and had his lower back massaged during a medical timeout between the fourth and fifth sets. He also swallowed pills administered by a doctor and grimaced visibly after many shots. Despite briefly rallying to take the second and third sets, he accumulated 70 unforced errors and was unable to hold off his opponent as the fifth set slipped away, the match ending just before midnight with Djokovic in tears. "My whole body starts to collapse — cramping and pain. The back just gave up in the end, and shoulder. I couldn't close it out," he said afterwards. "I pretty much despised every moment that I spent on the court."

Navone, a 25-year-old who won his first ATP singles title earlier this year at the Țiriac Open in Bucharest, Romania, held his nerve throughout despite facing a player he grew up idolising. "It was very tough because you are playing with the GOAT on this court," Navone said. "Five sets, against the GOAT — it's not something you do every day. It's a dream come true." It was also his first career five-set victory at Grand Slam level, a milestone that would have been Djokovic's 43rd such win.

The defeat deepens a troubling run for Djokovic, whose last competitive action before Cincinnati this month was a semifinal loss to world number one Jannik Sinner at Wimbledon. He had hoped that an early exit in Cincinnati — where he also lost in the first round — would give him extra time to prepare for New York, but the physical problems that have shadowed him throughout the season evidently persisted. In his post-match comments, Djokovic acknowledged he was "trying to address really what's going on and how far I can go this way," leaving open the question of whether Sunday's match may have been his last at this or any Grand Slam. The defeat falls exactly 21 years to the day of his US Open debut, lending the occasion an unavoidable sense of significance as the tennis world now watches to see what comes next for the sport's most decorated player.