World number four Novak Djokovic has made an early exit from the US Open, crashing out at the start of the tournament.

​Operativ Media reports that in the first round of the Grand Slam tournament in New York, the Serbian tennis player lost to Argentina's world number 49 Mariano Navone in five sets, 2-3 (6-7, 7-5, 6-4, 2-6, 1-6). During the match, which lasted 4 hours and 40 minutes, Djokovic experienced health issues, vomiting on court and having to take a medical timeout after the fourth set due to back problems.

​With this result, the 37-time Grand Slam champion suffered only the third first-round defeat of his career at a Grand Slam tournament. He had previously been eliminated in the opening round of the Australian Open in 2005 and 2006. This defeat will also push the athlete out of the top ten rankings for the first time since July 2018.

​Meanwhile, 25-year-old Mariano Navone became the first player to defeat his Serbian opponent in an opening match at the US Open. This victory also marks the South American athlete's first-ever win over a top-ten opponent in prestigious Major tournaments.

​As a reminder, the tournament, which features a total prize pool of $108 million, is being held on outdoor hard courts in New York from August 30 to September 13.