US Open: Novak Djokovic loses to Mariano Navone in longest first round match of his career in Grand Slams

Novak Djokovic fell at the first hurdle as his tilt at a record-breaking 25th Grand Slam came to a shocking end to Argentine Mariano Navone in a five-set marathon at the US Open.

The 39-year-old went down 7-6 (7-5) 5-7 4-6 6-2 6-1 to the world No 49 in a match that lasted four hours and 36 minutes.

It was the longest opening match of a Grand Slam in Djokovic's career and the earliest exit at a major since the 2006 Australian Open.

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Navone ended the Serbian's bid for a fifth US Open title as he struggled with physical problems in ‌oppressive humidity.

The Serbian was 42-12 in five-set matches, while Navone was 0-4 but Djokovic was unable to battle through as he struggled to move at times and vomited on multiple occasions.

With this defeat, the question now lingers as to whether this was Djokovic's final match at this or any Grand Slam.

"I didn't enjoy myself," Djokovic said. "I think it was obvious that it was an awful feeling on the court for me.

"It's something that I've been carrying, unfortunately, pretty much every match this year. Vomiting, throwing up, a serious issue there. Then my whole body started to collapse, basically cramping and pain.

"The back just gave up in the end and shoulder, and I couldn't close it out. Can the issue be fixed? I don't know. I'm trying, man. I'm trying. Let's see."

How an ailing Djokovic crashed out at Flushing Meadows...

The last time the Serbian great had been seen on a tennis court, in Cincinnati two weeks ago, he was collapsing to his knees and being sick into a towel.

After that defeat by Thiago Tirante, Djokovic revealed he had a "health issue" which he has been dealing with "for many years", and which affects him in heat and humidity.

It was certainly warm in New York but by no means Cincinnati levels, yet Djokovic's cheeks were already red and his hair drenched in sweat midway through the first set, which he had led 3-0 but lost in a tie-break.

Having already successfully lobbied to have the roof closed, and with his wife, Jelena, and kids watching from the stands, Djokovic hit back late in the second set - after throwing up by the courtside towel box - with the crucial break for 6-5 and then serving it out.

He was sick again midway through the third - despite the air conditioning switched on - but still took his one chance to break serve as he moved one set away from victory.

Djokovic vomited again at the start of the fourth before breaking once more for 2-1, but Navone - a 25-year-old from Argentina who earlier this year won his first ATP singles title - did not go away.

After firing a shot wide in the fourth set, Djokovic landed awkwardly and dropped his racket before all but conceding the fourth set.

Djokovic appeared to be cramping up and he could barely move as Navone struck back, winning just one more game in a dramatic defeat.

The Serbian, who was holding back tears at one point in the fifth set, ended up making 70 unforced errors in a painful performance that ended minutes before midnight in New York.

"I was a break up in the fourth, but just struggled all the way since the fourth game of the match," he added.

"I don't want to take too much out of his win. Congrats to him. He's a nice guy, a fighter. But, you know, I didn't enjoy myself.

"When it comes to the match itself and the overall feeling of how I felt with my body and playing, it was really not enjoyable. I pretty much despised every moment that I spent on the court for that."

He will fall out of the top 10 of the ATP rankings for the first time in eight years.

Tale of the Tape: Navone vs Djokovic

"It was very tough for me because you are playing with the 'GOAT' on this court," said Navone, who idolised Djokovic growing up.

"For sure it's the best thing I've had on court. This is an amazing court and the biggest stage. It's amazing, the way we play. I mean, five sets. I'm very happy. I don't know. What can I say?"

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