If the Knicks asked for anything for Christmas, it should have been to play better defense. Maybe they should make that their New Year’s resolution.

The Knicks’ Christmas Day performance — a 119-114 loss to Boston at the Garden — showed that they rely too much on their offensive talents and don’t put in the extra work on the defensive end.

It was only the third time all season that the Knicks’ big three of Carmelo Anthony, Kristaps Porzingis and Derrick Rose each scored 20-plus points in the same game. The Knicks are 1-2 when that happens.

“The game was all defense, the way that I look at it,” Rose said.

Rose has seen it that way a lot this season. He’s repeatedly said the Knicks have to commit defensively to have any chance to do something special, as they say they can.

After 30 games, they’re 16-14. It’s good enough to be among the top five seeds in the Eastern Conference, but it also is a prime indicator of how inconsistent they are.

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At the start of play Monday, the Knicks were the only team with an-above .500 record to allow more points (107.9) than they scored (105.6).

They ranked 25th in defensive efficiency, giving up 108 points per 100 possessions. The Knicks are the only team with a winning record to rank in the bottom 10 in that category and points allowed per game.

The Celtics weren’t exactly the Knicks of the early 1990s, but they made enough plays to win the game. And it was a game that only highlighted, in front of a national television audience, what has been the Knicks’ biggest weakness all season, their defense.

The Knicks made some costly mistakes and bad decisions late, and their ball movement throughout wasn’t great, with only 11 assists on 41 field goals. That speaks to Anthony and Rose getting most of their points in isolation. It’s worked for the Knicks, but it also works against them sometimes.

“We’re not the team that gets the most assists,” Porzingis said. “A lot of it is iso for guys and guys making one-on-one plays. I’m not really worried about that too much. Obviously, there are situations where we can give that extra pass or keep playing, but that wasn’t why we lost.”

It was the defense.

“We didn’t make the right decisions,” Porzingis said. “Throughout the game, we could have played much better in a lot of situations that could have saved us energy at the end.”

Only a handful of teams can allow 119 points and win, and the Knicks can’t count on being one of them.

Their high game this season is 118 points. They’ve allowed at least 119 four times and in three of their last nine games.

It’s also telling how the Knicks have fared against the better teams in the league. They’re 2-10 against teams that began Monday above .500. Six of those defeats were by double figures and three were by at least 28 points.

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“Yeah, I really hope that one day we can beat better teams,” Joakim Noah said sarcastically.

The Knicks have done a good job of taking care of the teams they should beat. But they’re never going to win consistently enough to achieve the goals they have set for themselves if they can’t put more emphasis on stopping the other team.