DETROIT — The complaining needs to stop.

That was the message ahead of Thursday’s Game 3 from Josh Hart, who singled out himself and Karl-Anthony Towns as the Knicks players who should cut out their in-game tantrums over calls.

“It definitely takes you off your game. I think controlling it, that just comes from within, kind of focusing on controlling what you can control,” Hart said. “We can’t control what they’re calling. We can’t control getting our first free throws with what, 17 seconds on the clock? We can’t control those kinds of things. We can just control how we respond to it. Last game, I responded terribly. I have to make sure I fix that, KAT fixes that, and move on from it.”

Controversial officiating was a big story of Monday’s Game 2 against the Pistons, mostly because the calls were so heavily skewed against the Knicks.

Tom Thibodeau’s squad didn’t attempt a free throw until 17 seconds remained in the first half. New York ended the 100-94 defeat with 19 free-throw attempts compared to Detroit’s 34, with the 15-shot discrepancy representing the biggest of the Knicks’ season — by far.

The NBA also determined the refs made an incorrect call on a potential Knicks go-ahead play with 76 seconds remaining, when Jalen Duren’s hack on Hart was ignored.

So the Knicks had legitimate gripes about Game 2. But it’s also one of those uncontrollable variables that is best ignored during games.

Several Knicks — but especially Hart, Towns, Thibodeau and Jalen Brunson — spent a solid portion of the Game 2 evening in animated verbal protest of the officiating, a tactic that never results in changing a call but can redirect a players’ focus from winning games.

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“We’ve had a lack of focus when it comes to that,” Jalen Brunson said. “We’ve gotta let them do their job and we’ve gotta do ours.”

Thibodeau railed on the referees in his Game 2 postgame interview, saying, “If [Cade] Cunningham’s driving and there’s marginal contact and he’s getting to the line, then Jalen deserves to be getting to the line. It’s really that simple.”

Pistons coach J.B. Bickerstaff countered with the series free-throw disparity between Brunson (10.5 per game heading into Thursday) and Cunningham (8.5). Bickerstaff also wrongly stated Wednesday that Brunson was No. 1 in free-throw attempts in the NBA playoffs — he was second behind Giannis Antetokounmpo — while Cunningham was ninth (he was 4th).

Regardless of the whistles, New York’s offense sputtered in Game 2. The ball stopped moving, the shots stopped falling and the attention to the referees increased.

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“I think we played too slow [in Game 2]. We probably could have been more forceful. Myself, I have to cut out the complaining and talking to refs,” Hart said. “So it’s just some of those things, things that are easily fixable. You learn from it, you grow from it and you try not to make the same mistakes in Game 3.”

Hart has had a complicated relationship with the referees. Last season, he led the Knicks in technical fouls with seven. Most of those were for yelling at officials. This season, Hart had six technicals by early January before making a commitment to better relationships with the referees. He even sought out a current official for advice.

“He was just like, ‘No, you’re an amazing competitor. But sometimes in the heat of competition, it’s like you’re against us, too. Like you look at it eight on five.’ Which I do sometimes,” Hart said at the time. “So I think my complaining and getting techs hurts us. We’re giving them free points or the ball or whatever it is and those kind of things.”

Hart and the Knicks were back to doing that in the playoffs. And they acknowledged it’s a problem.