DALLAS — Karl-Anthony pointed to the reason for the loss on the locker room board, where 26 percent was highlighted in red so it couldn’t be missed.

“St, this is the first half,” Towns said. “We didn’t shoot well. We didn’t shoot well at all.

Seven days and four games into their road trip, the Knicks are bearing symptoms of multiple personality disorder.

That was never clearer than in Wednesday’s 129-114 Thanksgiving victory at the Mavericks’ table, a Knicks loss in which their vaunted offense faltered under Jason Kidd’s shifting defense at American Airlines Center.

Two nights after the Knicks (10-8) set the NBA’s season-high 145 points with a win over Denver, they shot (protect your eyes, kids) 26 percent in the crucial first half.

“We couldn’t buy a basket to save our lives early in the game,” Jalen Brunson said. “Defensively we just weren’t there. It’s a long season. Honestly, we need to limit the ups and downs and be as stable as possible.”

The trouble was all over the box score, but best explained by OG Anunoby, who followed his career-high 40 points on Monday with by far his worst game as a Knick.

Anunoby, the team’s first-month MVP, shot 3 of 15 with eight points. He and Josh Hart, the two starting forwards, combined for two points on 0 of 13 from the field in the first half.

The Mavericks employed a rotating defense on screens, which has been a bugbear for Tom Thibodeau this season, and the Knicks had no answer for it.

“We give teams the game plan (to stop us),” Hart said, noting that the Celtics and Rockets also hampered the Knicks with that strategy.

The only reason their point total and overall shooting percentage (47 percent) looked respectable is because they racked up points in a short amount of time. The Knicks were never able to increase the deficit to single digits in the second half.

“I guarantee you, Jason Kidd is a heck of a coach,” Towns said. “He watched the game (against Denver) and found ways to play against us. He did a great job. They were ready.”

Towns and Brunson were the only weapons to combine for 62 points. Brunson had 37. Mikal Bridges had a quiet 20 points on 19 shots.

The ball movement stopped.

The Knicks managed just 20 assists, even with the extra assists, after tying the franchise record with 45 through two nights.

From the Suns’ loss a week earlier, to a dud against the Jazz, to a brilliant performance against the Nuggets, to a disaster against the Mavericks.

“Some nights you can look ridiculous and some nights you can look ridiculous the other way,” Brunson said. “Like I said, we have to strike a balance. It can’t be a roller coaster ride. For us, it has to be a steady gradient the whole way.”

The first quarter set the tone.

The Knicks’ high-octane offense, which entered Wednesday’s game second in the NBA in efficiency, managed just 15 points in that opening period with a series of terrible shots.

The Knicks missed 17 of their 21 attempts, including 0 of 8 from long range. They had two assists in the first quarter and trailed by 13.

Thibodeau’s troops never recovered.

The deficit was 22 at halftime and 19 after the third quarter. With about 90 minutes to play, Kidd, the Mavericks’ head coach, declared Brunson and Towns the “No. 1 pick-and-roll combination in the NBA.”

Then Dallas (11-8) shut out the rest of the squad. The Knicks bench was non-existent, with a total of 12 points between Cam Payne, Jericho Sims and Miles McBride.

“We’ve been going a long time,” Thibodeau said, suggesting the Knicks were either mentally or physically exhausted. “Early start (6:30 p.m. local time) but we have to get ready. And we got into this hole, and then it was hard to dig ourselves out.”

The Mavericks, meanwhile, got 23 points from Kyrie Irving and shot 56.5 percent. Quentin Grimes, the former Knick, was a two-way force and helped guard Brunson.

Luka Doncic missed his fifth game of six with a wrist strain, but the Mavs coped well without him and led 4-1.

A lot of this revolves around Irving, who owned the Knicks. He has won 19 of his last 21 duels against the franchise, including ten in a row. Irving hasn’t lost to the Knicks since his time with the Celtics in 2018.

And on Wednesday it was easy in the first 24 minutes

“We were terrible in the first half,” Hart said.