DALLAS — Carmelo Anthony came, scored and then sank.

Anthony notched 30 points, but went silent in the fourth quarter Wednesday, going scoreless while the Knicks’ defense crumbled in a 103-95 loss to the Mavericks at American Airlines Arena. Anthony finished with seven turnovers.

Kristaps Porzingis’ slump continued (13 points, 4-of-11), while point guard Derrick Rose (13 points, 6-of-15, three assists, three turnovers) failed to run the offense in a depressing fourth quarter that saw the Knicks commit eight turnovers and score just 22 points.
“You can’t have eight turnovers in the fourth and expect to win the game,’’ coach Jeff Hornacek said.

Anthony, who reportedly was shopped to the Cavaliers for Kevin Love, had 30 points entering the fourth but took just two shots in the quarter. It was the second time in three games he was blanked in the fourth.

“I thought we let our foot off the gas offensively — we weren’t as aggressive as we were in the first three quarters and turnovers went their way,’’ Anthony said. “It was more of us being careless with the basketball.’’

Courtney Lee put up his Knick-high 23 points, but it didn’t matter without help from Rose and Porzingis.

“It’s tough,’’ Porzingis said. “Nobody’s happy to lose a game like this. We wanted to finish the short road trip strong and win both games. We made a lot of mistakes. That’s what’s frustrating. Going forward if we want to still have a chance to make the playoffs, we have to beat teams like this.’’

With 30 seconds left, Anthony drove and had a pass to Ron Baker deflected. Baker raced to catch it on the baseline but was ruled to have stepped out of bounds, keeping the Knicks down four points.

“It was a bad pass,’’ Anthony said.

Off their big win in Indiana, the Knicks fell to 20-27, failing to muster a two-game winning streak in 2017.

“Definitely frustrating because we got the talent we were just 14-10 and now we’re fighting to not be last in the East,’’ Brandon Jennings said. “We haven’t been consistent.’’

In a strange risk, Hornacek inserted Baker at shooting guard early in the fourth quarter for defensive purposes, but he missed two straight open shots. When Rose returned, Jennings was removed with 6:05 left instead of Baker. Jennings looked perturbed.

“Just the flow of the game, if there’s five that’s rolling out there, regardless of who it is, they should stay out there and finish or keep it going,’’ Jennings said.

Rose let the offense get stagnant in the fourth and the Mavericks pulled back ahead 97-88. With 3:09 left, a Rose turnover was converted into a fast-break bucket for Dallas.

Rose stuck to his mantra that offense had nothing to do with the defeat.

“Defense — that was the entire game, lack of defense,’’ Rose said. “Turning the ball over is one thing but on the defensive end we don’t have any presence. It shouldn’t be like that.’’

Dirk Nowitzki scored 19 points and Harrison Barnes led the Mavericks with 23. Dallas (16-29) pulled away to a 10-point lead with 2:49 left in the third quarter. Anthony committed two bad turnovers during Dallas’ run and then he failed to close out on a Dorian Finney-Smith 3-pointer that jolted the Mavericks into a 75-65 lead.

Anthony looked to have something to prove in the first half — even more aggressive than usual. He scored 14 points in the first quarter. After hitting an extra deep 3-pointer he turned toward the fans in the midcourt seats and took extra glee in tapping his head with his fingers, as is his custom.

But there were no fingers to the head in the final quarter.