The NBA coach at the other end of the line Thursday afternoon wasn’t calling to gloat. More he was concerned.

“They’re not going to screw this up, are they?”

As much as the Celtics‘ 111-101 Game 2 loss to Miami can be attributed to the Heat living up to their moniker from beyond the 3-point arc, this veteran mentor was more concerned about the way the Bostonians approached the other end of the floor. It’s a concern he expressed to Heavy Sports in early March, and while the club has mostly been able to suppress the offensive issues that have plagued it in postseasons past, the coach thought the Celts might be getting too wrapped up in process.

Not to get all repetitive and stuff, but his warning then bears another look:

“The thing I worry about with Boston is that they sometimes hunt mismatches too hard, instead of just playing and letting them happen more organically,” he told us then. “When they’re whipping the ball around, damn, that’s some beautiful s*** to watch, and you’re thinking, ‘How the hell are we ever going to stop this?’

“But if you can slow them down, some of their guys get frustrated and try to make plays. They’re good enough to do it a lot of the time, but if it doesn’t work once or twice, it seems to throw them off on both ends.

“The thing is, the game slows down in the playoffs, and that’s going to be the challenge for them. They have to play with pace even in the halfcourt.”

Rough Night for Kristaps Porzingis

On Thursday, he added, “They were trying to take advantage of (Kristaps) Porzingis when Miami had smalls on him, but when he missed a few shots, he kind of got all messed up. He can sometimes have trouble with smaller guys who get low on him. Remember when (the Celtics) used to throw Marcus Smart at him?”

Porzingis certainly had a rough night, going 1 for 9 from the floor on the way to six points. The Celts were a minus-32 when he was on the court.

But the problems were much larger, with Miami able to capitalize for 20 points from 13 Boston turnovers.

“They were playing hard, but it got too mechanical at times when they were trying to overthink the matchups and the execution,” the coach said. “The funny thing is, they still probably win that game if Miami doesn’t go crazy on 3’s.”

Celtics Need to Cool Heat 3s

The Heat shot an upper middle class 37 percent on treys in the regular season, hitting 12.5 of 33.7 on average. On Wednesday, they bagged 23 of 43 (53.5 percent). They were 14 for 32 inside the arc.

“You can’t figure they’re going to shoot like that on 3’s again,” the coach said. “But Boston has to do something to cool them down. Miami got too many open looks, because it looked like Boston was intent on protecting the paint.

“But I still go back to the offense. When you’re off on the offensive end, it can easily affect how quick and connected you are on defense. It shouldn’t, but it does. Every coach has had to deal with it. The best thing (Joe) Mazzulla can do now is bitch at them about their defense and then turn them loose at the other end.”

And that’s not second guessing when you were saying it more than a month and a half ago.