Jalen Brunson's 44 points carried the Knicks to a crucial win Tuesday night. Newsday Knicks beat reporter Steve Popper breaks it down. Credit: Newsday/William Perlman

When the game was over, the handshakes started, and the Knicks headed to the locker room, all you had to do was look at the faces of the players to get a hint of what was on their minds.

The Knicks had just completed a 121-91 demolition of the Indiana Pacers in Game 5 and the remainder of the 19,812 fans at Madison Square Garden who hadn’t already spilled into the street were serenading the team with emphatic chants and cheers. But there were no smiles on the faces of the Knicks — instead the stern, serious expressions in place that they’d shown for 48 minutes.

The win pushed the Knicks ahead, 3-2, in the best-of-seven Eastern Conference semifinals with a chance to close out the series Friday night in Indianapolis, and the Knicks — with the same mindset that led to the domination on the court — insisted that until that fourth win is complete, the job is not done. Celebrations and smiles can wait.

“One thing I’ve learned in the playoffs is that one game does not have any effect on the next,” Jalen Brunson said after Game 5. “Whether you lose by one or lose by 30, it has nothing to do with the next game. So, honestly when we’re leaving here tonight, it’s all about how we prepare for Game 6.”

The game marked a massive turnaround from the Knicks' Game 4 loss at Gainbridge Fieldhouse that had tied the series with the Pacers. Making an in-series adjustment, Knicks coach Tom Thibodeau inserted Deuce McBride into the Game 5 starting lineup. The move provided not just an energy boost but, by downsizing the lineup, the Knicks still managed to play so much bigger.

The Knicks dominated the boards — Isaiah Hartenstein, the only player in the lineup not undersized in his matchup, grabbed 17 rebounds, including 12 on the offensive glass. The rebounding margin was 53-29, with the Knicks grabbing 20 offensive rebounds and Indiana countering with 24 defensive rebounds.

“What they did in Indiana, no one was proud of,” Hartenstein said. “We were kind of in the mud, but still, that can’t happen. So we just came together. We wanted to be more physical. We wanted to play Knicks basketball, and I think we got back to that.”

But it wasn’t just the rebounding that marked the difference in effort and intensity. The Knicks stood up when the game grew heated. The Pacers were hit with a pair of technical fouls and Knicks were hit with three, and it was in those skirmishes that they believe they revealed their true character — and that of the Pacers.

“They were talking, trying to be physical, basically trying to be our brand, our identity,” Donte DiVincenzo said. “And they were successful with it last game. And we regrouped, watched film and realized that’s not who we are. We came out tonight and that’s exactly who we are.”

Who the Knicks are is a team that follows its leader — Brunson. And Brunson provided the reason to believe, dominating the Pacers’ defenders after days of hearing talk of how Pacers coach Rick Carlisle had devised a way to slow him down. With the insertion of McBride into the lineup, setting screens to get the defender that the Knicks wanted on Brunson or force double-teams, suddenly there were openings everywhere for shots and open paths to the rim for rebounds.

The Pacers may adjust to that, but the question remains that if the Knicks reclaimed their identity — the blue-collar bunch who shrugs off expectations and doubters and just outworks opponents — can the Pacers match that?

Thibodeau has built this team on the belief that, even with four key rotation pieces missing, they have the players who can get the job done, that fatigue is a concept they don’t accept, and that each day is a building block toward the next. And the next now is Game 6.

“To me that’s been a trademark of the team,” Thibodeau said. “We’ve been shorthanded all year, and this is our way. We have to play hard as heck on every possession and we gotta keep doing it. So gotta do that for 48 minutes and we know if we defend and we rebound, take care of the ball, we’re gonna have a good chance to win.

“I think that’s sort of the nature of the playoffs, in particular as a series goes on, because you’re playing the same guys over and over. I have great respect for them. I think it’s great competition, and that’s what you love about the playoffs. I think you see in every game now there’s a lot at stake and guys are competing real hard. I think it’s enjoyable for everyone. I think fans love it, and we understand what we have to do and we just gotta make sure we’re ready for the next one. We can’t feel too good about this.”