Djokovic's tearful loss leaves future uncertain

Be warned: Novak Djokovic has made a fool of those who have doubted him before.

Some questioned if the Serb would challenge for the sport's top honours again after he dropped out of the world's top 20 amid a two-year major title drought in 2018.

Djokovic proceeded to win four of the following five Grand Slams, doubling his tally of majors with 12 across the next six years.

But three years have now passed since he landed his men's record 24th major title at the US Open.

And, as the 39-year-old fought back tears mid-match on Sunday night, this latest loss in New York felt different.

Staring at a first opening-round Grand Slam exit since 2006, one of sport's all-time greats simply had nothing left, beaten 7-6 (7-5) 5-7 4-6 6-2 6-1 by Argentina's Navone.

For so long now Djokovic has not only defied time, but appeared to be improving with it.

That was evident at this year's Wimbledon, where he outlasted Felix Auger-Aliassime, 14 years his junior, in a five-set thriller that became the longest quarter-final in the tournament's history.

Even in his late 30s, Djokovic has been the one challenging Jannik Sinner and Carlos Alcaraz, the new dominant forces in the men's game.

At the Australian Open in January, he ended Sinner's bid for a third-straight title in a sensational five-set comeback victory. He then led Alcaraz by a set in the final, before fading to a four-set defeat.

After early exits in Paris and New York, there is an inevitable sense that Melbourne was his best chance to secure an outright record 25th major triumph and cap a career unparalleled in every statistical measure.

Djokovic was despondent after the match, saying he "despised every moment I spent on the court for that".

"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," Djokovic said.

"But, from the perspective of the crowd and support, it was incredible.

"I'm very sorry that I didn't perform as well as I should have, could have, or wanted - for them."