You thought this was going to be easy?

You thought because the Knicks had stomped out the Boston Celtics in six games that the party would just keep rolling? You thought that after waiting 25 years to see an Eastern Conference finals game at Madison Square Garden that the show would be better than this?

Well, you thought wrong. A four-day, citywide celebration of Knicks greatness ended with a thud Thursday when the Knicks fell apart in the final minutes of regulation and were beaten, 138-135, in overtime, by the Indiana Pacers in Game 1 of their best-of-seven series.

The crowd at the Garden watched with their mouths agape as the Knicks blew a 14-point lead with just under three minutes remaining as Aaron Nesmith brought the Pacers back with a flurry of threes. Nesmith scored 20 points in the fourth quarter, including hitting six three-pointers in the final 4:45 of regulation.

Yet, the image that will forever be imprinted in the mind of Knicks fans is of Tyrese Haliburton who officially became the modern-day Reggie Miller when he celebrated his long jumper at the end of regulation by running around the Garden floor with his hands around his neck in a choke sign. Haliburton initially thought he had hit a three at the buzzer and won the game for the Pacers, but upon review it was ruled as a 2 and the game went into overtime.

The fact that the Knicks couldn’t repair and get it done in the final minutes of overtime just underscored the fact that fans had witnessed one of the greatest postseason collapses in Knicks history, which you can bet certainly wasn’t what they had paid $700-plus to watch.

“We didn’t finish the game out. We didn’t run through that finish line,” Josh Hart said. “I feel like we defensively let off the gas. The intensity and physicality weren’t there. Offensively we were playing slower, a little stagnant, and looked like we were playing not to lose.”

It was a stunning contrast to the way the Knicks had competed in the first two rounds when they were the team making furious comebacks. The Knicks came back from being down 20 points twice against the Celtics to win games.

In the days since closing out that series against the defending champions, the Knicks have been celebrated in New York like they haven’t been in decades. The Empire State Building was awash in orange and blue light, and the city announced Wednesday that it had renamed a street for every player on the Knicks roster.

In some ways Nesmith’s flurry of threes combined with Haliburton’s choke sign was an homage to Knicks-Pacers history.

“I wasn’t plotting to do it or anything,” Haliburton said. “Everybody wanted me to do it like last year at some different point. But it’s got to feel right, and it felt right at the time. If I had known it was a two, I would not have done it. So, I think I might have wasted it . . . I don’t plan on using it again.”

Karl-Anthony Towns grew up in New York a Knicks fan and is well-acquainted with their history. He didn’t seem to be all that thrilled to have helped write The Choke Game II.

“I mean it’s our job to make history so we’re not here to repeat history,” Towns said “We’re here to make history, so that doesn’t pop into my mind. I have to think about the present and what we can do now so we can make our own history.”

The Knicks have now lost home-court advantage, and now have to figure out a way not to fall down, 0-2, when they host the Pacers for Game 2 on Friday. Brunson, whose 43 points weren’t enough to save the Knicks, said they have their work cut out for them.

“Yeah, in the playoffs when you win it’s the best thing ever. When you lose it’s the worst thing ever,” Brunson said.

“So the best way to deal with all that is just stay levelheaded, make sure we have each other’s backs. Obviously not the way we want to finish the game.

“Tomorrow we watch film, get better, and make sure we’re ready for Game 2.”