Denis Shapovalov has been fined $7,000 (£5,623) after hitting umpire Arnaud Gabas in the eye with a ball during Canada's Davis Cup tie against Great Britain, the International Tennis Federation has announced.
The 17-year-old Canadian smashed a ball in anger during the third set of the deciding rubber against Kyle Edmund, hitting umpire Arnaud Gabas in the eye, and was immediately defaulted.
Shapovalov could have been fined up to a maximum of $12,000 on site by referee Brian Earley but the unintentional nature of the offence and his remorse will have been taken into account.
The ITF could take further action, imposing a larger fine or even a ban, but a spokesman for the governing body told the Press Association no additional punishment is anticipated.
Gabas was taken to Ottawa General Hospital as a precaution but no damage to the cornea or retina was found. He will see his personal eye doctor in France on Tuesday for a further examination.
The fine is less than that handed to David Nalbandian following the Queen's Club final in 2012, when the Argentinian was defaulted after kicking an advertising hoarding into the leg of a line judge and penalised $10,000 -- along with his prize money and ranking points.
It will undoubtedly be a big lesson for Shapovalov, the reigning Wimbledon junior champion and one of the brightest young talents in the game.
He immediately apologised to Gabas and then sat with his head in his hands while the umpire composed himself sufficiently to announce the end of the match, sending Britain through to an away quarter-final against France in April.
An emotional Shapovalov said: ''I feel incredibly ashamed and embarrassed and I just feel awful for letting my team down, for letting my country down, for acting in a way that I would never want to act.
''I can promise that's the last time I will do anything like that. I'm going to learn from this and try to move past it.''
The force with which Shapovalov hit the ball was extraordinary -- had it missed the umpire it may well have hit someone in the crowd -- but it is not the first time in recent months a player has pushed the limits.
Novak Djokovic may well have been defaulted from the French Open last year had a line judge not moved swiftly to dodge a racket he bounced off the court in anger.
The world number two was then involved in an exchange with a reporter after being asked about an incident at the ATP World Tour Finals in London in November where he hit a ball into the stands.
Andy Murray, meanwhile, kicked a ball in frustration during a match in Cincinnati last summer that nearly hit the umpire.
Canada captain Martin Laurendeau admitted players tread a fine line.
He said: "The codes are out there, it's up to the officials to implement abuse of balls, abuse of rackets.
"There's grey lines. You can smack a ball between line judges and if you don't hit anyone you're okay, you can continue, but if you hit his leg or an arm then it's an automatic default."
The Shapovalov incident almost certainly did not change the outcome of the tie, with Edmund leading 6-3, 6-4, 2-1 and seemingly on his way to a comfortable victory.
But it was not the way Britain wanted it to be decided, and was a shame for Edmund, who handled a potentially difficult situation with great aplomb.
The 22-year-old fought back tears of disappointment after his performance against Vasek Pospisil on Friday, which he branded "pretty dismal", and had never played a deciding rubber in Davis Cup before.
But he showed no nerves and defused the power and exuberance of Shapovalov expertly.
Both Britain's last two victories in the competition have come without Murray, demonstrating the much improved strength in depth at the highest level.
Captain Leon Smith insisted he had no clue yet whether Murray would return for the France tie, where the world number one will surely be needed if Britain are to stand a chance of making further progress.