Novak Djokovic checks a line judge after hitting her with a ball in reaction to losing a point against Pablo Carreno [Source: AP]

Novak Djokovic was kicked out of the U.S. Open for accidentally hitting a line judge in the throat with a tennis ball after dropping a game in his fourth-round match.

This was a stunning end to his 29-match winning streak and bid for an 18th Grand Slam title.

As he walked to the Arthur Ashe Stadium sideline for a changeover, trailing Pablo Carreno Busta 6-5 in the first set, Djokovic — who was seeded and ranked No. 1 and an overwhelming favorite for the championship — angrily smacked a ball behind him.

The ball flew right at the line judge, who dropped to her knees at the back of the court and reached for her neck.

During a discussion of about 10 minutes near the net involving chair umpire Aurelie Tourte, tournament referee Soeren Friemel and Grand Slam supervisor Andreas Egli, Djokovic appeared to be pleading his case. But eventually, he walked over to shake hands with Carreno Busta.

Tourte then announced that Djokovic was defaulted, the tennis equivalent of an ejection.

“I was a little bit in shock, no?” Carreno Busta said later at a news conference done via video conference.

Djokovic quickly left the tournament grounds without speaking to the media.

Asked whether Djokovic should have been allowed to continue to play, Carreno Busta shrugged and replied: “Well, the rules are the rules. … The referee and the supervisor (did) the right thing, but it’s not easy to do it.”

Indeed, the U.S. Tennis Association issued a statement saying that Friemel defaulted Djokovic “in accordance with the Grand Slam rulebook, following his actions of intentionally hitting a ball dangerously or recklessly within the court or hitting a ball with negligent disregard of the consequences.”

The USTA went on to say Djokovic forfeits the ranking points and $250,000 in prize money he earned in the tournament — “in addition to any or all fines levied with respect to the offending incident.”

This is the latest way in which Djokovic finds himself at the center of the tennis world for a reason other than his best-in-the-game returns, can’t-miss groundstrokes and body-contorting defensive prowess.

Djokovic tested positive for the coronavirus — as did his wife, one of his coaches and other players — after participating in a series of exhibition matches with zero social distancing he organized in Serbia and Croatia in June.

Then, on the eve of the U.S. Open, he helped establish a new association he says will represent men’s tennis players.

And, of course, there’s been his dominance on the court.

Djokovic began the day 26-0 this season and with an unbeaten run that extended to his last three matches of 2019. He had won five of the past seven Grand Slam tournaments to raise his total to 17, closing in on rivals Roger Federer, who has a men’s-record 20, and Rafael Nadal, who has 19.

With reigning U.S. Open champion Nadal, who cited concerns about traveling amid the pandemic, and Federer, sidelined after two knee operations, not in the field, the 33-year-old Djokovic was expected to claim a fourth trophy in New York and gain on them.

But it all came apart so suddenly Sunday, even if it was clear that Djokovic did not intend to hit the line judge. He wasn’t looking in her direction when his racket made contact with the ball, and there was concern written on his face as soon as he realized what happened.

But players who hit a ball out of anger and make contact with an on-court official have been defaulted in the past.

In 2017, for example, Denis Shapovalov — the 21-year-old Canadian scheduled to play his fourth-round match Sunday night — was defaulted from a Davis Cup match against Britain when he accidentally hit the chair umpire in the face with a ball.

At Wimbledon in 1995, Tim Henman hit a ball into the head of a ball girl and was defaulted from a doubles match.

“I think the supervisors and all them are just doing their job, but very unlucky for Novak,” said Alexander Zverev, the No. 5-seeded man, who reached the quarterfinals by winning Sunday. “If it would have landed anywhere else — we’re talking a few inches — he would have been fine.”