In Jayson Tatum, Mike Krzyzewski sees the maturation of a young talent he helped nurture – The Boston Globe

“Thank God,” Krzyzewski thought to himself. “And a little bit of, ‘It’s about time.’ ”

As building legends go, what Tatum did across the final four-plus minutes of that Eastern Conference semifinal game is destined to be a foundational moment, going from one of the worst offensive nights of his basketball life to one of the best.

In forgetting the horror show of 12 misses in his first 13 attempts, in personally outscoring the 76ers in the final quarter, in leading the Celtics to a come-from-behind victory, Tatum wrote a story that accounted not only for his otherworldly physical skill set but for his mental toughness as well.

He never quit, and when that crucial shot finally fell — the first of four vital 3-pointers in the fourth quarter — the man who had coached him back in college, the coach who’d helped him believe he could be one of the game’s greatest players, could all but predict what would come next.

“With talent, all you need is to light the match,” said Krzyzewski, the former Duke coach. “And he lit the match. And all of a sudden he had a four-minute fire. If you’re a Celtic fan, it’s a beautiful thing.”

The story only got better from there, with Tatum’s 51-point outburst in the clinching Game 7 propelling the Celtics to the Eastern Conference finals for the third time in four years.

And when Krzyzewski flips the channel to Game 1 of that series against Miami (“I’ve watched them all,” he said of the Celtics’ playoff run so far through Atlanta and Philadelphia), what he sees is a story of maturation, of growth, and of ongoing evolution.

From the moment Coach K convinced the kid from St. Louis’s Chaminade Prep to head to Durham, N.C., that desire to improve was evident.

“He’s one of the best players in the world right now, and the thing, besides physically taking care of himself at a high level all the time, but with that investment and him being a father for this long, he’s matured,” Krzyzewski said.

“In other words, he’s not prone to get down on himself. A great player doesn’t get down on himself or herself. They can make a correction while they’re having a poor performance. They don’t have to wait and watch and find out why; they self-analyze. That’s the maturity of a great player, and that’s what I saw in him.

“Obviously there’s some stop action, end of quarter, a timeout, or whatever. But I think doing that fourth-quarter thing was maybe his best performance because it came after doing not well, and it came within the game.

“Then, in Game 7, 51 points is spectacular, but he started out that whole thing, he was prepared for something great. In the sixth game, he was not prepared for it. He was prepared to lose that game.

“And I just think it’s great maturity, great competitive maturity, to go along with exceptional talent to do what he did. That’s what makes the great ones. You know. And he showed that.”

The show is far from over, and with the talent that surrounds Tatum on this Celtics roster, with the shadow of last season’s Finals loss to the Warriors still looming, nothing short of a title is a palatable ending. Krzyzewski knows Tatum knows how to win — the longtime USA Basketball coach watched his former charge win a gold medal for the US in the 2020 Olympics — but there’s nothing like an NBA title to lay the final brick of a permanent legacy.

“With the organization they have, the team they have, they’re right there,” Krzyzewski said. “And of course that puts you on a different level when you actually win the NBA championship. The MVP conversation, he’s right there, too. In other words, he’s right there for all the things. Not every great player gets them. But he’s still young. They have a team that could win it.”

Led by the player who can anchor it, the one who stood on that court in Wells Fargo Center after his miraculous in-game rebound and answered a question about how he’d done it by saying, “I’m one of, humbly, one of the best basketball players in the world.”

Knowing how much Tatum has going on — playoff run, father to 5-year-old son Deuce — Krzyzewski doesn’t text him often. But he couldn’t help it. He had to reach out after Tatum’s candid response.

“I can’t tell you exactly what I texted him after they won it, but I started it out with, ‘Humbly, you are mm, mm, mm,’ ” Krzyzewski said. “I think I put a smiley face with it.

“I loved how he said that, ‘Humbly I’m one of … ’ He doesn’t want to brag. He should have said he is one of the great players on the planet. And maybe that’s what he told himself in that fourth quarter.

“When we talked to the Celtics about the draft, I said I think he’s the best player, and I know he’s the best offensive player. I’ll tell you he’s coachable. He’s unbelievably coachable.

“To me, he’s been a learner. He has not fought learning, sticking with something old when he sees it’s not working and someone brings to his attention how he can improve. Not just on the court. His discipline in nutrition, training, all of it is at the highest level. And so he has learned and he’s disciplined and he’s still open to more learning.

“This kid, he’s not a kid anymore. This guy — he’s got it.”

Tara Sullivan is a Globe columnist. She can be reached at tara.sullivan@globe.com. Follow her on Twitter @Globe_Tara.