NBA

Knicks’ heartbreaker hurts so good

In their hearts, they knew. They had seen Amar’e Stoudemire hesitate ever so slightly as he squared up from beyond the 3-point arc, beyond the top of the key. They had seen the bright red rectangle bordering the backboard flash in that eye-blink before the ball left Stoudemire’s fingertips, even if they badly wanted their eyes to lie to them once the ball splashed through the twine.

Sure they knew. The Knicks knew. The 19,763 people in the stands knew (minus Spike Lee, that is, who wanted to share a bold word or two with a Celtic or three).

They knew, and didn’t care. The Knicks hugged each other and jumped on each other and waited for the scoreboard to reflect a 119-118 victory. The crowd knew, and didn’t care, roaring like it was 80 degrees and May outside, not 20 degrees and December, a bellow that came from the deepest reaches of their soul, from so many nights when they’d been forced to stay quiet as a novitiate.

“I wasn’t sure if it was good or not,” Stoudemire said later. “But it felt good.”

And here’s the thing: Even after Bill Kennedy, Courtney Kirkland and Leroy Richardson conferred at the replay table, even after Doc Rivers kept waving the shot off with a wry grin on his face, even after the Celtics wound up receiving the favorable verdict and executed their own interpretive victory dances … even after all that, it still felt good.

It hurt so good.

And think about it: When was the last time you twisted and tossed and turned after a Knicks game, the way you surely did last night? This is what it means to be relevant. This is what it means to matter again.

“I told the guys that if they were handing out the trophies tonight it would be hard to take,” Knicks coach Mike D’Antoni said when it was over, when the Celtics sprinted for their locker rooms with the 118-116 final frozen on the scoreboard, official in the scorebooks. “But we have 50, 60 more games left and this was a test. We matched them point for point.”

He smiled a pained smile.

“We just have to get a little bit better.”

The truth is, they are more than a little bit better, and this was an affirmation of that. Yes, the Celtics were missing some beef in Shaquille O’Neal, in Jermaine O’Neal, in Kendrick Perkins. Yes, when it mattered most, they have a lineup stuffed with closers, and two of them — Ray Allen with a late 3, Paul Pierce with the game-winning jumper — stepped up when they were needed most, rending moot the fact that the Knicks either led or were tied, unabated, from 2 minutes and 25 seconds into the game until 1:02 remained in it.

In a lot of ways, this was a loss that gained the Knicks so much more than any of their 16 victories had. Kevin Garnett might have sprinted off the court, defiantly spewing expletives, but you know he understands the Knicks are on the come.

“We definitely earned our respect,” said Stoudemire, an absolute beast again last night with 39 points and 10 rebounds. “I guarantee you that Boston respects us. We are not slouches. We are going to play every single night until the horn goes off and Boston knows it.”

They found out for sure last night. Pierce’s virtuoso step-back 14-foot jumper over Stoudemire’s outstretched hands seemed to give the knife a final twist with four-tenths of a second left, threw a cold bucket of water on a Garden crowd that had burned throughout a back-and-forth fourth quarter, marveling at a splendid swapping of big plays and huge shots.

It was over.

And then it wasn’t. Stoudemire received the ball. He squared. He fired. And the ball barely touched the net. For a half a heartbeat, Pierce and Allen looked as if they had contracted food poisoning, except none of the refs signaled it was good. Because it wasn’t. If you saw the play with your eyes, not your heart, you knew. Stoudemire needed an extra tenth of a second.

But it was fun while it lasted, wasn’t it?

michael.vaccaro@nypost.com