His initiation to the Stanley Cup Playoffs came early. Out came Matt Rempe for his first shift over a minute into Game 1 for the Rangers.

Immediately, he heard the MSG sellout crowd chant, “Rempe, Rempe!!” Ever since his arrival, the 21-year-old former 2020 sixth round pick has taken the city by storm.

There was the welcome to the NHL moment from well-respected Islanders veteran Matt Martin in the Stadium Series played at Met Life Stadium on Feb. 18. A game the Rangers rallied to win 6-5 in overtime.

After getting ejected in his third game versus the Devils for an illegal check on Nathan Bastian, Rempe had a memorable fourth game in a 2-1 win over the Flyers on Feb. 24. He took on Nicolas Deslauriers early. Then, Rempe scored his first career goal when he had the puck deflect off him for the game-winner.

There was the lesson he got taught by Mathieu Olivier in a loss to the Blue Jackets. He battled veteran Ryan Reaves to a draw against the Maple Leafs.

In a rematch with the Devils, Rempe was given the gate for an elbowing major that concussed Jonas Siegenthaler on Mar. 11. Following serving a four-game suspension that set the stage for what happened on Apr. 3 at MSG, Rempe was ready to take on Kurtis MacDermid in what turned into a line brawl.

In 17 games, he had a goal and assist with a whopping 71 penalty minutes and 50 hits. When Rangers coach Peter Laviolette decided to play him over Jonny Brodzinski for the final two games of the regular season, it was a vote of confidence for Rempe.

Indeed, he made his playoff debut on Sunday afternoon at the World’s Most Famous Arena. The Garden came alive when the cult hero shocked everyone by scoring the first goal of Game 1 against the Capitals.

It came when linemate Barclay Goodrow made a pass to Jimmy Vesey, who quickly sent the puck in front for Rempe to bury for the big goal early in the second period. The reaction in the building told the story.

The Rangers erupted for two more goals to build a 3-0 lead. Artemi Panarin and Jimmy Vesey followed it up to give the Blueshirts three goals in 2:06 to break it open. They took the first game 4-1 over the Caps.

Rempe nearly had another goal later. It was a successful postseason debut. One that the Calgary native will remember. He played in front of his Mom for the first time at The Garden. It was special.

“I think I’m built for the playoffs,” Rempe told reporters at his locker following the victory.

“It’s pretty cool. Today was the first day my Mom was at The Garden ever. It was really special because she had to get a chance and get a goal for us. It was really special for her to be there.

Asked if he had some juice due to his Mom being in the building, he quipped, “I always got juice,” with a grin. “I always got some juice. Obviously, I love her so much. She’s my biggest fan.”

For his first ever postseason game, Rempe had an impact. He finished with a goal, three hits, and some pleasantries exchanged with Dylan McIlrath near the conclusion. They’re familiar with each other from the AHL.

It was quite a day for Rempe. He gets to do it again on Tuesday.