Novak Djokovic, disqualified from the US Open for inadvertently hitting a female line judge in the neck with a ball slammed in frustration, is not the first and will not be the last sporting champion to lose his temper and do something stupid.
As the current world number one tennis player noted in an Instagram post following the abrupt fourth-round end of his apparent progress towards an 18th Grand Slam singles title, the official in question suffered no lasting physical harm.
"I checked on the lines person and the tournament told me that thank God she is feeling okay," he wrote.
"I'm extremely sorry to have caused her such stress. So unintended. So wrong."
But the more you look at the clip of the incident on social media – when last I checked it had more than 10 million views – the more bizarre and disturbing it appears.
Having required lengthy treatment to his shoulder after falling while at 5-5 in the opening set against Spain's 20th seed, Pablo Carreño Busta, and having then lost his serve to go 6-5 down, the 33-year-old Serbian swipes a ball towards the back wall as he walks across court.
It flies, unerringly, towards the throat of the official, who has just clasped her hands behind her back, and she staggers before sinking to the ground.
Djokovic physically starts, before raising his left hand in acknowledgement of his action and walking over to the prone form in front of him. It looks bad.
Novak Djokovic (-125), the #1 seed in the tournament just got defaulted from the US Open after hitting the line judge in the neck pic.twitter.com/dvJQgLPFfA— Barstool Bets (@barstoolbets) September 6, 2020
In a statement, the United States Tennis Association said: "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 US Open tournament referee defaulted Novak Djokovic from the 2020 US Open.
"Because he was defaulted, Djokovic will lose all ranking points earned at the US Open and he will be fined the prize money won at the tournament in addition to any or all fines levied with respect to the offending incident."
Djokovic's disqualification followed exchanges with officials lasting several minutes.
Television broadcasts picked up Djokovic saying "you told me you have a choice" and "you have a game penalty, set penalty, many options".
But tournament referee Soeren Friemel told BBC Sport there was not "any chance of any opportunity of any other decision other than defaulting Novak because the facts were so clear, so obvious" and that there was "no discretion involved".
Friemel added: "His point was that he didn't hit the line umpire intentionally. He said 'yes, I was angry, I hit the ball, I hit the line umpire, the facts are very clear, but it wasn't my intent, I didn't do it on purpose, so I shouldn't be defaulted for that'.
"We all agreed that he didn't do it on purpose but the facts are still that he hit the line umpire and that the line umpire was clearly hurt."
Among the reactions that have come crowding in following this aberrant incident is one from Billie Jean King, the former world number one who won 12 Grand Slam singles titles between 1966 and 1975, and who has been a pioneer in developing the women's game.
"Here are my thoughts on the Novak Djokovic default," she tweeted. "First I hope the line judge is okay. The rule is the rule. It is unfortunate for everyone involved, but in this specific situation the default was the right call."
Here are my thoughts on the Novak Djokovic default.— Billie Jean King (@BillieJeanKing) September 6, 2020
First I hope the line judge is okay.
The rule is the rule. It is unfortunate for everyone involved, but in this specific situation the default was the right call. #USOpen
We've seen similar incidents in tennis down the years. Britain's usually right and proper favourite Tim Henman was defaulted from, of all tournaments, Wimbledon in 1995 after accidentally hitting a ball girl in the head with a ball after losing a point.
In 2012, Argentina's David Nalbandian was disqualified from the final at the Queen's Club Championships after injuring a line judge in the shins by kicking an advertising board.
In 2017, Canada's Denis Shapovalov was defaulted in a Davis Cup tie after inadvertently hitting a ball into the umpire's face, while last year Australia's Nick Kyrgios was disqualified from the Italian Open after hurling a chair onto the court.
But this is not the first time Djokovic has acted in this fashion. At the 2016 French Open he admitted he was "lucky" not to have hit a line judge after hurling his racket to the floor.
At the ATP Finals later that year, the Serbian responded sharply after being challenged by a member of the press after he had knocked a ball into the crowd.
"You guys are unbelievable," he said at the time. "Because you're always picking these kind of things. I'm the only player that shows his frustration on the court? That's what you are saying? It's not an issue for me. It's not the first time I did it."
After Djokovic was defaulted, Britain's Davis Cup captain Leon Smith told BBC Radio 5 Live Sports Extra that he thought the Serbian should have had a warning earlier in the match when he slammed a ball into an advertising hoarding after the Spaniard had saved three set points.
"There has to be consistency, if someone hits a ball with that much venom and temper, call a warning," Smith said.
"The second one can be dangerous and so it proved to be."
This startling incident prompts once again an unoriginal phrase – "moment of madness" – and an equally unoriginal but inevitable question: "What was he thinking!?"
As Philip Larkin wrote, in response to a rather broader query:
"Ah, solving that question
"Brings the priest and the doctor
"In their long coats
"Running over the fields."
And right now psychological speculation is having a field day.
Has Djokovic's equilibrium been affected by the testing and controversial year he has already had? In June he was one of several players to test positive for coronavirus after taking part in the Adria Tour event he organised in Serbia and Croatia.
Although Djokovic insisted the organisation had "met all health protocols" there was widespread criticism, particularly given that players were pictured dancing close together in a Belgrade nightclub and then taking part in a basketball match.
He conceded that it had been "too soon" to stage the event – but later referred to what he believed had been a "witch hunt" against him.
His public profile received further questioning when he was accused of being opposed to vaccines – although he later denied this.
More recently Djokovic has created waves throughout the game by setting up a breakaway players' union – the Professional Tennis Players' Association – which seeks greater powers and rewards for the leading names in the sport than have been available under the stewardship of the Association of Tennis Professionals.
Roger Federer and Rafael Nadal have been among those questioning the wisdom and timing of this move, and Britain's Andy Murray has called for Women's Tennis Association members to be involved.
In 2017, Djokovic faced another huge challenge in his career when, just a year after becoming only the third male tennis player to hold all four major Grand Slam titles at once, his form faltered dramatically amid injuries and what he described as "personal problems".
At the time he told the press: "For me, it's a whole new situation that I'm facing.
"Especially in the last seven, eight months, not winning any tournament, which hasn't happened in many years.
"I guess you've got to go through it, try to learn your lessons and figure out how to get out of it stronger. It's a big challenge, but I'm up for it."
The challenge he faces to his career and the public perception of him is now every bit as great.
At that time I recalled, and now recall again, sitting with Djokovic's parents, Srdjan and Dijana, and his youngest brother Djordje, as he reached the third round at the 2006 Wimbledon Championships by beating Spain's 11th seed, Tommy Robredo, in straight sets.
His mother alternately nibbled at her finger and clenched her fist in the air. Father Srdjan chewed his gum with manic rapidity. Ten-year-old Djordje offered fierce tactical advice from under his red baseball cap.
Afterwards, Dijana, chic and tanned, settled back in her chair as the head settled on her Guinness in one of the court-side bars. "It is my favourite," she said with a smile that had barely left her face since seeing her boy – the youngest in the draw at just 19 years and one month – march on.
He was on an extraordinary upward trajectory. It all seemed so simple for him back then…