OG Anunoby's nonchalant reaction to his audacious game-winning three pointer in Game 3 of the Toronto Raptors' second-round NBA series with Boston garnered almost as much social media attention Thursday night as the shot itself.

Anunoby's muted response came as no surprise to his high school coach, however. Blair Thompson, who coached Anunoby at Jefferson City High School in Missouri, says Anunoby has always carried an understated swagger in high-pressure situations.

"He's made 1,000 big plays in his life from late shots to big steals, big rebounds and huge dunks where the whole gym erupts, and he's the only guy standing there like he's seen it before," Thompson said Friday from Pacific, Mo., where he is the activities director at Pacific High School.

"Now I think inside, he's having a lot of fun with it. But he's one of those guys who's not going to show you a lot of that on the outside."

Anunoby's winning shot Thursday came with a half-second left on the clock and the Raptors down two points. So inevitable did defeat look for the Raptors that a Toronto news station had already reported that the Celtics had taken a virtually insurmountable 3-0 lead in the best-of-seven Eastern Conference semifinal.

Instead, Anunoby lost his defender on the baseline, received a perfect, cross-court inbounds pass from point guard Kyle Lowry -- past seven-foot-five Celtics defender Tacko Fall, no less -- and drilled a shot that gave Toronto a 104-103 win.

As the shot went in, Anunoby walked off the court looking like someone who had just filed his taxes rather than potentially saving the Raptors season. Lowry, by comparison, wore a grin from ear to ear as the point guard and his teammates mobbed the six-foot-eight forward.

"I don't think that's anything out of the norm for OG," Thompson said. "I think he has a lot of passion for the game, and I think he's one of those guys that, good or bad, he's not going to show a lot of emotion.

"Not to say that he doesn't have it, but he does a good job at keeping everything even-keel and I think that helps his game too. Not going too far up or too far down, just right down the line and keeping it about business."

"He expects a lot of himself and he's always been willing to put the work in, and those are usually the guys that aren't surprised when something good happens for them," Thompson added.

Raptors coach Nick Nurse called it "one of the most classic reactions of all time.

"I just saw it for the first time about 10 minutes ago and I'm like, that brings a smile to your face," Nurse said Friday.

Nurse said Anunoby's stoic reaction reminded him of Celtics legend and former Indiana Pacers coach Larry Bird.

"I can't remember exactly the scenario but it was Larry Bird as a coach and probably Reggie Miller made a step-back three to win the game and Larry Bird didn't even move, he didn't blink, he didn't put his arms up," Nurse said. "The camera went right to him, I remember that as another classic reaction to a game-winning shot."

Thompson said there is a love of the game underneath Anunoby's low-key approach.

"That's all you're really trying to foster from a coaching standpoint is keeping kids accountable and letting them play loose and have fun, and OG's always managed to do that," he said. "He's a great guy to be around. He may not be over-the-top personality wise, but he's a funny guy, he's got a great sense of humour and he's personable.

In his third season in Toronto, Anunoby is transforming from a "3-and-D" guy -- a defensive specialist who can also spread the floor with a decent three-point shot -- to a more complete player. He has improved his handling and is more capable of creating his own shot close to the net.

He has scored in double digits every game this series for the Raptors, including 20 points in a Game 2 loss, while still providing elite defence. He reached his career-high for points in a game this season, scoring 32 in a road loss to Denver on March 1.

"I think OG has been underrated his whole career," Thompson said. "Part of that is he was very late developing physically. What you see now, it took a lot of years for him to mature into that. I think his ceiling has always been higher than everybody around him, it's just taken him some time to grow into that.

"There's really nothing he can't do well on a basketball floor. He's a perfect combination of talent, hard work and physical gifts. I think he'll keep developing, because I believe he wants to be one of the elite players."

Thompson said he is still in touch with Anunoby and has enjoyed watching his career progress.

"I always like ribbing him and stuff about different things when I do get a chance to talk to him, just like any other coach would," Thompson said. "We usually keep it light when we talk or we text back-and-forth. I just want to make sure to let him know that I'm watching him, and I'm proud of him and support him.

"It's been really fun to see how far he's come and I'm really excited for him, and I try to let him know that every chance I get."

This report by The Canadian Press was first published on Sept. 4, 2020.