This Knicks fan base is running out of patience. The feeling has to be mutual from Knicks ownership and management. Because a nine-game slump was not on the bingo card of Knicks possibilities entering this season.

Yet there the Knicks were, at Madison Square Garden on Martin Luther King Jr. Day, as the boos began to filter in over the course of a disappointing first half that would stretch into a 114-97 loss to the Dallas Mavericks on Monday.

The Mavericks beat the Knicks — who Mike Brown declared, at long last, fully healthy — without stars Anthony Davis and Kyrie Irving, centers Daniel Gafford and Dereck Lively II, plus role players D’Angelo Russell, PJ Washington, and Dante Exum.

And they beat them thoroughly, right out of the gate, turning a 13-4 lead into a 30-point first-half advantage Dallas would never let go of. Fans in attendance sensed their Knicks go of the rope early.

That’s why they booed. They booed once after the loss in front of Knicks royalty to the Phoenix Suns on Saturday, a game Jalen Brunson and Josh Hart both sat with ankle injuries.

This time was different. The Knicks faithful booed their team on four separate occasions in the first half alone on Monday, each smattering of disapproval a response to a Brown timeout as the Dallas lead swelled over time.

The Knicks have now lost nine of their last 11 games. They have fallen from the realm of championship contender to the glut of teams that can call themselves pretenders. And each loss has been more embarrassing for the last, particularly for Brown, who, in his first year on the job, has experienced the highest highs and the lowest lows of coaching in the Mecca of basketball.

Brown, after all, installed the changes that helped the Knicks win the third-ever NBA Cup playing a free-flowing, fast-paced, three-point heavy style of play. They have since fallen off of a cliff in every recognizable way.

The New York Knicks are broken, and there’s no telling what in-house fix could be in store — if one exists — to get this team back on track.

All the while, Madison Square Garden, quite possibly the most electrifying venue in all of professional sports, hosted a silent party in the fourth quarter. They were speechless at the state of affairs of their team, a word that could also be used to describe owner James Dolan, who left his usually baseline seat and did not return in the second half.

Dolan’s Knicks, after all, traded RJ Barrett and Immanuel Quickley for OG Anunoby then signed him to a franchise record $212.5 million contract. They traded Julius Randle and Donte DiVincenzo to the Minnesota Timberwolves for Karl-Anthony Towns. They traded five first-round picks for Mikal Bridges then signed him to a four-year, $150 million extension over the summer. Then they fired the head coach who authored back-to-back 50-win seasons and the team’s first Eastern Conference Finals appearance this century and hired Brown to install more up-tempo, modern systems on both sides of the ball.

The results were inconsistent at best, until the Knicks slipped into the spell that’s undone their season. And for Brown, the going has gotten worse since the NBA Cup.

Brown took an embarrassing loss in his return to Sacramento, where the Kings put a belt to the rear of the coach who they’d fired last season. He took tough losses in Detroit, where the Knicks lost by 31, and on Saturday, on Knicks homecoming night, in front of the very players whose jerseys could one day join the ranks of those hanging from the rafters.

Monday might be the toughest loss of Brown’s early Knicks tenure. Not only did his Knicks lose to a depleted Mavericks team, but Brown, as a coach, lost to the Knicks’ first option. He lost to the coach the Knicks front office wishes it hired, a coach who has full command of his team regardless of who’s on the floor.

So now it’s time to fire up the trade machine. Because this team as currently constructed is spiraling well outside of its head coach’s control — provided the front office is still sold on Brown being the man for the job at MSG in the first place.

Brunson and Hart returned to the rotation on Monday after quick bouts with ankle injuries, but on the day of his announcement as a second-time NBA All-Star starter, Brunson shot just 9-of-24 for 22 points and six assists.

Towns finished with 22 points and 18 rebounds but turned the ball over five times, shot 9-of-19 from the field, and recorded five fouls for the fourth game in a row.

Hart, OG Anunoby and Mikal Bridges each finished with less than 10 points, with Bridges shooting 3-of-10 for seven points in 32 minutes and Anunoby scoring nine points on eight shot attempts after combining for 46 points on 37 shot attempts in the previous two games with Brunson sidelined.

The Knicks, at full strength, got just 27 points from their bench, which only saw Jordan Clarkson play two minutes and miss all three of his shot attempts in that span. And Guerschon Yabusele, who the Knicks signed to their largest salary cap exception during the offseason, didn’t touch the floor until there were just over two minutes left in the fourth quarter.

Meanwhile the Knicks, who were constructed this way because of their defensive versatility but couldn’t stay in front of Collin Gillespie in Saturday’s loss to Phoenix, couldn’t stay in front of Jason Kidd if the 52-year-old former ball wizard decided to check himself into the game on Monday.

They certainly couldn’t do anything with Naji Marshall, the brute-force bucket who hung 19 points, most of which came as early damage in the first half. The Knicks couldn’t stay attached to Max Christie after he made his first two threes and allowed him to hit eight on 10 attempts from deep on the night. They couldn’t stop Klay Thompson — in a down year — and the ex-Warriors Splash Brother hit four threes with his girlfriend, award-winning artist Megan Thee Stallion, sitting courtside at MSG.

And they can’t stop this losing streak, bringing us back to the boos at The Garden, which rained down even more after the final buzzer sounded on Monday.

Those boos were the most faint of the night. Because a Knicks fan base that usually stays until the very end has begun to quit on this team.

And it’s only a matter of time before the person responsible for signing the checks follows suit.