Kenny Atkinson called it “devastating.”

No, not Tuesday’s Eastern Conference finals opener, in which his Cavaliers blew a 22-point fourth quarter lead to the Knicks.

He was referring to Game 6 of the opening round, specifically RJ Barrett’s game-winning 3-pointer that bounced off the back rim and dropped in, forcing a Game 7. 

The point: Heartbreak isn’t new to this group of Cavaliers. They are well-versed in adversity, having survived two elimination games to get to this point. 

“We’ve been through it in the playoffs,” the Cavaliers coach said Wednesday after a walk-through inside the Garden. “I’m more like, ‘OK, here it is. This is what it’s about.’ You live between misery and awesomeness in the playoffs, and this is of course misery. But this is probably the fourth miserable game we’ve had in the playoffs. It’s like, ‘OK, get back on the horse.’ ”

Atkinson wasn’t trying to diminish the pain of the setback, and nor were his players.

The Cavaliers were in position to take home-court advantage, dominating the Knicks for three-plus quarters. MSG was quiet. The home team looked rusty. 

Then, everything went wrong for the visitors. 

“We gave them a game,” reserve guard Dennis Schröder said. “At the end of the day, we controlled the game — I think 90 percent of the game we controlled it. The last 10 percent, they did a great job. You have to give them credit, too, for not giving up and making shots at the end, and that was the game.” 

There was a lot to like before the collapse at both ends of the floor. Donovan Mitchell scored 26 points on 11-for-17 shooting in the first three quarters. Big men Jarrett Allen and Evan Mobley were giving the Knicks fits. Cleveland didn’t look like such a big underdog. 

“I want to lean on the positive,” Atkinson said. “We had three quarters of really good basketball — some of the best basketball we’ve honestly played in the playoffs, offensively and defensively.”

The hope for the Cavaliers is their experiences throughout this postseason will help them Thursday and beyond. This is a team that shook off the Barrett shot, that rallied from a 2-0 deficit to take down the top-seeded Pistons in the Eastern Conference semifinals and win Game 7 in Detroit in emphatic fashion. 

“Just understanding that we didn’t have the best effort last night, we didn’t have the best outcome,” Allen said, “and the resiliency is going to show [Thursday] how we come out. 

“Just have confidence in yourself and the team, and know that we have to go get one [in Game 2].”