NBA

Celtics fail to execute down the stretch

Paul Pierce buried a 3-point shot with 1:20 left in the third quarter and the Celtics were riding a 70-63 lead as visions of a Game 1 and ultimate first round playoff series over the Knicks upset danced in their heads.

But from that point on, covering the final 13:20, the Celtics went belly-up in their 85-78 Game 1 loss to the Knicks at the Garden.

What happened?

“I don’t know to be honest,” said Kevin Garnett.

The “why” is from any number of reasons, the “who” was everybody dressed in green and the “what” read like a list of Basketball 101 sins. Yes, the Knicks defense was great, but the Celtics offense was awful, and they blamed themselves.

The Celtics scored eight points, all in the fourth quarter when they committed eight turnovers, seven of them near-impossibly in the final 5:30. They shot 3-of-14 (.214). Pierce, their No. 1 guy, finished shooting 6-of-15. Garnett was 4-of-12. Jeff Green, a first half monster, was invisible after halftime. The bench was outscored, 33-4.

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“Offensively,” Pierce said, “we’ve got to do a better job with our execution. We turned the ball over too much, allowed them to get offensive rebounds in the fourth. That’s huge in a playoff game when you turn the ball over, when you don’t execute.”

Well, the Celtics certainly turned the ball over and did not execute. And the Pierce-Garnett duo accounted for 13 points after halftime, 11 by Pierce and seven of those in the third quarter.

“Ball movement is a big part of our offense,” Garnett said. “We can say the ball got a little stagnant.”

Or a lot stagnant.

“We turned the ball over a ton and our spacing was horrendous in the second,” said coach Doc Rivers who will go back to the drawing board before Tuesday’s Game 2.

“I didn’t think we lost our composure. We lost our way on the floor,” Rivers said. “We just stopped playing the right way.”

The Celtics came away from the mess feeling they kicked one away — up seven under two minutes left in the third quarter, up three entering the fourth, still within four with 5:30 left. Then — and we’re not making this up — travel, bad pass, made jumper by Pierce, bad pass, missed 3-pointer, bad pass, lost ball, missed 3-pointer. Not exactly the game plan going in, you know?

“Some were forced, some were bonehead plays,” Pierce said of the turnovers.

“They were playing good defense but it was definitely us. We weren’t moving the ball like we were in that first half,” point guard Avery Bradley said.

“If we had those turnovers in any game we should probably lose, and we did,” Rivers said. “We were making post passes from the other side of the floor. Those are just not good passes.”

All the while, they were scoring eight points in the final 13:20. Also frustrating: The Celtics defense wasn’t bad.

“But we’ve got to put the ball in the hole,” Garnett said.