INDIANAPOLIS -- The Knicks will know exactly whom to blame if they miss the playoffs by one game, and which game ultimately cost them.

They were riding high, leading by 17 points with less than a minute left in the third quarter and were on their way to their third win over the Pacers in less than three weeks. But the Knicks collapsed and suffered a crushing 112-104 defeat Tuesday night.

Baron Davis used the words "bad," "disheartening," "discouraging" and "ugly" after this utter meltdown, which included the ejection of J.R. Smith with 10.7 seconds left after he lost his cool and threw Leandro Barbosa down on the court.

"We somewhat self-destructed," interim coach Mike Woodson said. "We kind of lost our composure."

"That's one that we all got to take blame for, everybody in the locker room," Tyson Chandler said.

The Knicks (27-27) were dismal defensively and completely outworked when it counted. Indiana outscored the Knicks 42-17 in the last 12:55, and by 40-17 in the fourth quarter. The Pacers opened the fourth on a 29-6 run.

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Instead of going 2½ games up on the Bucks for the eighth and final playoff spot in the Eastern Conference, the Knicks' lead was cut to 11/2.

"They just outworked us," Carmelo Anthony said. "We kind of got lax going into the fourth quarter. And they ran away with it.

"I think we got a little bit complacent, being up 17."

Anthony carried the Knicks with a season-high 39 points, including 12 of their 17 in the fourth. After they fell behind by eight, Anthony helped make it a one-possession game late. But he couldn't come through at the end.

With the Knicks down 105-102 with about 42 seconds left, Anthony had the ball and an open look at a potential tying three. It rattled out. Danny Granger made 1 of 2 from the foul line with 38.9 seconds to go to make it a four-point game.

Anthony was upset with himself after missing that three-pointer, but he had to rebound quickly and had another good look from deep on the next trip. He misfired again, leading to two Paul George foul shots and a 108-102 Indiana advantage.

"They both felt good," Anthony said. "They came out. Despite that, we were up [by 15 points] going into the fourth. For us to give that lead up, it was just unfortunate. We can't have that."

Granger led Indiana (32-21) with 27 points, 14 in the fourth. George added 18. Louis Amundson had only four points and five rebounds, but he by himself worked harder than the Knicks did in the fourth.

Landry Fields scored 15 points, and Chandler had 12 points and 14 rebounds.

This game started a rough stretch for the Knicks, who were without Amar'e Stoudemire (back) and Jeremy Lin (knee surgery) for the fifth consecutive game. Their next three games are Thursday at Orlando, home against the Bulls and at Chicago. After that, the Knicks play at Milwaukee, which should be a huge game for both teams.

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They can't afford many more letdowns or meltdowns, especially from Smith, who said it was "the frustration of the game," and that he "got a little fed up" with the pushing and shoving.

With all of the injuries, the Knicks need Smith to produce off the bench. Woodson said he would speak to his volatile sixth man.

"I'll sit down and talk with J.R. and just tell him he's got to be a little bit more professional," Woodson said. "He was frustrated. I could see that, as that fourth quarter lingered on. And maybe I should have pulled him. But I didn't. He and I will have a discussion about that, because that's a little unprofessional, I think."