NEW YORK -- Novak Djokovic arrived in New York prepared to hit the reset button on his reputation and continue his quest to surpass Roger Federer and Rafael Nadal on the Grand Slam board. He also sought to emerge as a political leader and reformer in the eyes of his peers.

Instead, the 33-year-old, 17-time Grand Slam singles champion skulked out of the USTA Billie Jean King National Tennis Center early Sunday evening, refusing to meet with the media after he was defaulted from the US Open for inadvertently striking a line judge in the throat with a ball he smacked in anger over a lost game.

The incident that led to the disqualification of the top seed occurred in the first set of his fourth-round clash with No. 20 seed Pablo Carreno Busta. With Djokovic serving a break point at 5-5, Carreno Busta outfoxed him with a passing shot to secure the 6-5 break.

Djokovic, head bowed in disgust, yanked a spare ball from his pocket and hit it toward the back netting. The ball struck the standing line judge, who dropped to her knees.

Djokovic's hopes to pull within one Grand Slam singles title of Nadal -- and two behind Federer -- collapsed as a stunned television audience at this fan-less US Open looked on, watching as the officials convened on the court to decide Djokovic's fate.

Shortly after Djokovic slung his two large, black racket bags over his shoulder and left the court in Arthur Ashe Stadium for a long walk down a completely empty hallway, Alexander Zverev, the No. 6 seed who had already advanced to the quarterfinals, said, "I mean, look, it's unfortunate. He [Djokovic] hit a ball, he hit a tennis ball. It's very unfortunate that, you know, he hit the line judge -- and especially where it hit her.

"If he would have hit it anywhere else, if it would have landed anywhere else ... we are talking about a few inches ... he would have been fine."

But you know what they say about tennis: It's a game of inches. Djokovic has benefited from that as much as anyone. Perhaps he should have been more prudent, aware that the rule is likely to manifest anywhere at any time.

But prudence has not been Djokovic's strong suit lately. That helps explain why he's such a compelling, successful champion. Nothing pleases him more than finding himself outmaneuvered by an opponent. He manages to turn a hopeless defensive position into a lethal, offensive one. It's why Nadal, after he mastered Djokovic in the 2013 US Open, said, "Novak is unbelievable. Sometimes I myself wonder how it is I can beat him."

Until Sunday's debacle, Djokovic had been riding a remarkable winning streak: 26-0 in 2020. He has been on an extended roll since 2011. As such, it should hardly be surprising that a touch of overconfidence has crept into his persona. That might be the factor that has turned this into such a difficult year for Djokovic -- at least since he collected his most recent major title at the Australian Open at the beginning of February.

After laboring for years as the third wheel in the Federer-Nadal rivalry, Djokovic hit his stride both as personality and as player. He carved out a distinct, but no less powerful, positive identity. He immersed himself in tennis politics, taking the lead in sketching out the vague outline of a new players' association that would improve the lot of his fellow pros, including those of average and lower rankings.

As this ultimately ill-fated event for Djokovic got underway, he said of the six-month lockdown caused by the pandemic: "I was playing and playing and playing, and I guess something like this needs to happen in order for all of us to really, OK, just take a deep breath and see what is most important in life. I mean, it really touched me. I was very grateful to have this period."

But the period of which he spoke so fondly turned out to be one marked by curious missteps. The first occurred in mid-April, when he expressed an anti-vaccination stance in a Facebook livestream, saying, "Personally, I am opposed to vaccination, and I wouldn't want to be forced by someone to take a vaccine in order to be able to travel."

Later in the spring, as USTA officials embraced the grand ambition to host the US Open at its scheduled time with a host of health protocols in place, Djokovic emerged as a leading naysayer. He bridled at many of the restrictions players might be asked to face, objecting strenuously to the idea that he, like everyone else, might be limited to bringing one guest. He told Serbia's Prva TV that it would be impossible for him to compete in the US Open because "the rules that they told us that we would have to respect to be there, to play at all, they are extreme."

That stance didn't play well with many of the lower-ranked players who were suffering economic hardships and hoping for a chance to play again -- exactly the players Djokovic was purporting to represent and fight for if and when his players' association matured.

The greatest miscalculation of all was the cavalier way Djokovic organized and presented his ill-fated Adria Tour. Although the Serbian government green-lighted the enterprise, the flagrant lack of social distancing (the players, led by Djokovic, were filmed dancing shirtless in a crowded Belgrade nightclub) led to a number of positive COVID-19 tests. Djokovic and his wife were among them, though they manifested no symptoms.

"We tried to do something with the right intentions," Djokovic said, citing the charitable goals of the tour. But many were disappointed by what they perceived as an assumption by Djokovic that the tour could not possibly be a bad idea because it was his idea.

Djokovic came to New York in need of a public relations win, and it looked for a week-and-a-half like he might score one. He won the Western & Southern Open, the front end of the "double-in-the-bubble" ending with the US Open. He made grand pronouncements about his new players' association.

"I am proud that we managed to do it," he said. "This is not my idea or [co-founder] Vasek Pospisil's idea. We were just executing something that the previous generations in the last 20-plus years have attempted to do, and they have not managed to make that final step."

Djokovic also sang a different tune about the US Open and New York City after the flattening of the curve of the pandemic allowed USTA officials to stage the tournament with slightly less onerous restrictions. He talked about how much he loves New York, saying he hoped all along to come and play.

"I congratulate the USTA, ATP, everyone who has been involved to make this happen," Djokovic said. "It's not easy. ... This is not only about us top-100 players, you know. This is about the tennis ecosystem in general."

Djokovic loves the word "ecosystem," and he seemed to enjoy the ecosystem set up for the players by the USTA at the National Tennis Center. As a seeded player, he had a luxury suite all to himself and his entourage. He commuted to the National Tennis Center from a rented home, expressing sympathy for the vast majority of players who had to tough it out "not being able to open their window and being in a hotel in a small room."

Andy Murray decided to forgo the rental home because of the "astronomical cost." He said he was content in the hotel. A champion of women's rights, Murray also told the media that he would not sign up with Djokovic's group because female players were not included in the plans, which Djokovic later disputed.

"I think they [Djokovic and Pospisil] felt like they needed to do what was best for them," leading WTA pro Sloane Stephens said. "The women were not included in that."

Others called out Djokovic for being tone-deaf.

Winning is a tonic, a good cure for almost any challenge in an athlete's life. The agency granted to Djokovic by that glittering whatever-0 record has been a powerful force. His success at a game of inches has been remarkable for a long time now. It's easy to see how he could grow accustomed to that. It could fill a man with hubris, making him think he's infallible.

And then he's not.