Knicks guard Jalen Brunson walks to the bench during a timeout...

Knicks guard Jalen Brunson walks to the bench during a timeout in the second half of Game 4 against the Pacers in an NBA second-round playoff series Sunday in Indianapolis. Credit: AP/Michael Conroy

INDIANAPOLIS — As the first half came to an end, Jalen Brunson grabbed Pascal Siakam by the uniform, angrily jawing with the Indiana Pacers forward, as Knicks coaches raced out to steer Brunson toward the locker room.

It was as much fight as the Knicks showed in the half as they were outshot, outworked and outplayed, falling behind by as many as 30 points. Whether it was the arduous fight the team has endured to get to this point, with injuries and workload finally catching up with them, or just one of those days when nothing went right, it was a humiliating performance all around  in  a 121-89 loss to Indiana at Gainbridge Fieldhouse that sent the best-of-seven Eastern Conference semifinal series back to Madison Square Garden tied at two games each.

Maybe that fight the Knicks have shown all year just isn’t enough when fatigue sets in, when the body count grows too high. Tom Thibodeau waved the white flag in the third quarter and addressed the team afterward, turning the page — but not before the team spoke up, with players rising when the coach left the room to send the message forward for Tuesday’s Game 5.

“I mean, we can talk about fresher legs, and you can give us all the pity that we want,” Brunson said. “Yeah, we’re shorthanded, but that doesn’t matter right now. We have what we have and we need to go forward with that. So there is no ‘we’re shorthanded.’ There is no excuse. There’s no excuse whatsoever. If we lose, we lose. That’s what that was.”

The Knicks looked a step slow at the start and the gap grew as the game wore on. They fell behind by as many as 43 points before Thibodeau finally relented, pulling his starters one by one in the third quarter. He finally yanked Donte DiVincenzo with 44.3 seconds left in the quarter, sending Daquan Jeffries into the game for him.

“We didn’t come out with the right energy,” Josh Hart said. “Game like this, we needed to be flying around, needed to be physical. We didn’t do that. We know what we did. We know this wasn’t us. Now we’ve just got to watch the film and get ready for Tuesday.

"I put that on my shoulders. I’m supposed to be the energy guy of the team and I didn’t do anything. I gave nothing. I put that on my shoulders. Now we’ve got to focus on rest and recovery and like I said, get ready for Tuesday.”

Thibodeau's decision to pull his starters that early was  an indication of just how futile his team's effort was. Each game of this series — and really, of the entire postseason for the Knicks — had been a nail-biter, but this was  a head-scratching performance.

The Pacers have upped their physicality in the last two games, and Brunson reacting — not just to Siakam but also to T.J. McConnell earlier — seemed out of character. He pinned it more on frustration with the performance.

“I mean they’re definitely physical, and when you’re down 30, nothing’s easy,” Brunson said. “Nothing’s flowers and roses, but yeah, we have to take this L. There’s no excuse, there’s no blaming anything, there’s no excuses of what we have or don’t have, or how anyone’s feeling or what. We take our Ls and we move forward.”

Thibodeau shifted his starting lineup for the second half, inserting Deuce McBride in place of Precious Achiuwa in a brief hope that a smaller lineup could change their fortunes. But then he removed  Hart first, an indication of what was to come. Isaiah Hartenstein — who had been banged up in the first half, coming down hard on his left shoulder — followed him to the bench. Brunson exited with 2:32 to play in the quarter before DiVincenzo finally left the court.

Even Alec Burks, who scored 20 points off the bench, was given a reprieve, with McBride inserted back in to replace him. It was left to Shake Milton, Jericho Sims, Mamadi Diakite and Jeffries to run out the clock on this game.

The numbers before the starters were pulled were just abysmal on both sides of the court. Brunson had 18 points but was 0-for-5 from three-point range and appeared to be short with nearly every shot. DiVincenzo shot 3-for-13 and Hart played only 23:51, finishing with two points and three rebounds. The Knicks shot 3-for-26 from beyond the arc in those three quarters.

And they presented no resistance to Indiana. No Pacer played more than 28 minutes and Tyrese Haliburton, who was listed as questionable before the game with an assortment of ailments — lower-back spasms, sacral contusion, right ankle sprain — led them with 20 points.

Thibodeau was blunt and simple in his explanation.

“Fell behind early,” he said. “Didn’t respond well. So better fix it.”

When asked how the Knicks can fix it, he said, “Get ready for the next one.”