Adam Fox is the only defenseman ever to win the Norris Trophy before playing in an official NHL playoff game. And when No. 23 made his debut Tuesday night in the Rangers’ 105-minute, 58-second adventure of a Game 1, a 4-3 triple overtime loss to the Penguins, he played at a Norris Trophy level.

“Fox being Fox” following a few months of, “That’s not like Adam,” is among the best news coming out of the opener for the Rangers, who in Game 2 on Thursday will face what is as close to the first must-win situation of head coach Gerard Gallant’s tenure as they’ll get until actually facing elimination.

The Blueshirts need their best players to be their best players from start to finish. Igor Shesterkin, who made 79 saves, more than held up his end of the bargain in Game 1. So did K’Andre Miller, who led the club with 44:38 of ice time, and so did Fox, who played 10 seconds fewer than that.

“I would definitely say it was my first playoff game,” said Fox, who played in those three (dis)qualifying games under the hermetically sealed bubble in 2020. “That atmosphere and intensity were completely different. Obviously I would like to have had a different result, but it was fun to be a part of.”

Fox’s underlying numbers were misleading after he took a bit of a beating in his 11:34 of matching up against Sidney Crosby. The idea is to contain No. 87 in his own end and not allow his line, which includes Jake Guentzel and Bryan Rust, to gain speed through the neutral zone and force the defense to back in. The Rangers gave away much too much good ice in Game 1.

“I think being more physical is one thing we can do,” Fox said. “They have a group of pretty smart players on that line so I think you also have to be mentally smart and be in the right positions.

“Being physical, moving your feet and trying to stay in front of them is big. We want to slow them down a little bit and not let them get so much time and space.”

Fox was a choreographer in Game 1, moving the puck out, directing and generating the attack. He opened the scoring with a first-period power-play goal from the top on the club’s only man-advantage of the marathon. His neat dish off an Artemi Panarin relay nearly set up Ryan Strome for the winner with 4:15 remaining in the first OT.

What’s more, Fox played with some musculature, too. He was credited with four hits, including one on which he plastered Brock McGinn seven minutes into the match.

He appeared to be playing on instinct and to his strengths after a few months of perhaps overthinking it or putting too much on himself. The 24-year-old just didn’t seem like himself after suffering an upper-body injury that sidelined him for the three games leading into the All-Star break. But he sure was on Tuesday.

“I don’t think I was nervous,” said Fox, who had seven shots on 10 hits in addition to his hit total and a game-high six blocked shots. “Obviously you get a little bit of the butterflies before a big game just in general, but I think it was more excitement, just being at home and knowing you have the crowd behind you.

“After those first few shifts you settle in and treat it like another game. The first 10 [minutes] are usually the most intense, people are just trying to get in a hit or keep it simple. The longer the game goes, you’re just trying to keep it more simple.

“With a game that goes that long, your legs are tired, you’re trying to not make mistakes and keep it a little more simple but overall I don’t want to change too much,” he said. “I’m just trying to play the same way and ramp up that intensity a little bit.”

Fox’s right-side fixture and companion, Ryan Lindgren, is dealing with a lower-body issue that he incurred during the third period of the April 29 regular-season finale against Washington. Lindgren missed the first 17:26 of the third period, played through both of the first two overtimes, but did not emerge from the room for the third OT.

Hence, Fox got 7:46 of five-on-five time with Patrik Nemeth, 5:16 with Miller, 2:46 with Jacob Trouba and 1:16 with Braden Schneider. Fox played 83.16 percent of his five-on-five minutes this season and 72.08 percent during his three years in the league with Lindgren. Gallant said that Lindgren is “banged up a little,” but is expected to play in Game 2.

If not, or if No. 55 — who may not have been bloodied as much this year as last, but has been physically punished as well as punishing — is simply too compromised to be an asset, then the coach would have to choose between Nemeth and either Justin Braun or Libor Hajek to become Fox’s sidekick. Gallant will not break up the Miller-Trouba tandem.

Losing Lindgren would not be ideal. But Fox back to being Fox most certainly is.