Denis Shapovalov has admitted he would never have been able to forgive himself if Davis Cup umpire Arnaud Gabas had been seriously injured by his ball-blasting antics on Sunday.
Shapovalov was immediately defaulted against Great Britain's Kyle Edmund after angrily striking a ball, which then inadvertently caught Gabas in the eye.
The 17-year-old's moment of madness cost him the match, which Edmund was already leading 6-3 6-4 2-1, and Canada the tie, as Britain won 3-2 to reach the quarter-finals.
Shapovalov has since been fined 7,000 US dollars (Â£5,623) by the International Tennis Federation, but while Gabas was left with a visible bruise, hospital checks showed no lasting damage to his cornea or retina.
"I'm very lucky that he is okay, because if things had gone worse I don't think I would have been able to forgive myself and I don't think I would be able to move past it," Shapovalov told BBC Radio 5 Live.
"After everything had happened I was in the locker room and I was asking if I could go see him, see if he was okay.
"I got a chance to talk to him and he was actually so good about it, which was very mature of him. It was such a stupid move for me to do something like that, so for him to be accepting and he was even joking around about it with me.
"He was saying things like I had the whole stadium, and that it was going to leave a nice mark. He told me he was okay."
Shapovalov believes he "blacked out" for around 10 minutes after the incident occurred and insists smashing balls in frustration is not typical of his on-court behaviour.
The reigning Wimbledon junior champion also expressed regret for Edmund and the British team, who were denied the satisfaction of completing a hard-fought victory.
"I also wanted to apologise to the British fans and to Kyle and the whole British team," Shapovalov said.
"At the end of the day I was down a break in the third set and if the match had continued I would have fought on, but the odds are that Kyle being the great player he is and being down two sets to love I would have lost the match.
"I feel bad that I didn't allow the British team to have the celebration that they deserved."
Gabas was taken to Ottawa General Hospital for precautionary checks and the French official said he felt fortunate to have escaped a more serious injury.
"I came off the court looking like Rocky Balboa," Gabas was quoted as saying in several national newspapers.
"The video is quite shocking to look at. We have to avoid some balls during the season but this one I had no chance. I feel quite lucky it wasn't worse."