INDIANAPOLIS – When they last played at Gainbridge Fieldhouse, many Celtics celebrated afterwards by drinking beer in the visitors’ locker room. On Wednesday, returning to the building where they had booked a trip to the NBA Finals, the Boston players had the more sobering experience of failing to mount a major comeback.

Jaylen Brown followed his team’s 135-132 overtime loss to the Pacers by sitting quietly in front of his locker for several minutes. Brown, who had a scowl on his face the entire time, didn’t immediately shake off the defeat. Such strong reactions are often reserved for bigger games, but his three-point miss with five seconds left could have tied the score, and he blamed himself for more than that final shot.

“Just our energy was lackluster,” Brown said. “A lot of that fell on me.”

Shortly after Brown pointed the finger at himself, Jayson Tatum did the same. Like Brown, he had missed a key shot in overtime, but Tatum expressed more frustration with the approach he brought to the court. Even as he scored 37 points, including a three-pointer to force overtime, he thought he had let his team down.

“I really didn’t like how I started the match,” Tatum said. “I feel like I set the tone in a negative way. My energy wasn’t where it needed to be. And I just felt like that had a domino effect. We were a step behind offensively and defensively, so I take a lot of the blame for that. I just wanted to pick it up in the second half.”

The Celtics almost had a stunning escape, but allowed Pascal Siakam to score the last 5 points of the game. After Siakam tied the score at 132-132 with 36 seconds left, Boston looked for a quick shot to earn a two-on-one opportunity, but Tatum missed a step-back 3-pointer that his team would have taken the lead. Siakam then hit a go-ahead 3-pointer, which stood as the winning basket after Brown fired a long jumper over Bennedict Mathurin on the Celtics’ final possession.

Brown liked the chance on the final shot, but said he thought his miss was indicative of the way he played.

“I just didn’t have my legs under me,” Brown said. “I thought it was a beautiful sight. I didn’t have my legs under me all night. No explosion, no eruption, and I think that cost us.”

Final pic.twitter.com/3WhmAo3VuD

— Boston Celtics (@celtics) October 31, 2024

Boston’s two All-Stars were hard on themselves after their first loss of the season. While both could have rued big misses in overtime, they seemed more upset at their failure to play with their normal lead early in the game. While trailing by as many as 24 points, the Celtics shot just 6-for-15 from the restricted area in the first half, including 2-for-7 from that range during the second quarter. Their missed layups sparked a Pacers offense that had struggled through the team’s first four games.

“We put ourselves in a hole early in the game but didn’t convert open looks,” Brown said, “we weren’t physical enough on drives and ended up at the rim. And a lot of that came from me, I have to be better for my guys.”

The Pacers lost three of their first four games this season. Their offense, which rarely slowed down last season, finished an ugly 23rd. Rick Carlisle said they were still trying to regain the lead that got them to the Eastern Conference finals and gave Boston problems in that series. Although the Celtics prevailed in a sweep, the Pacers tested them as much as any other playoff opponent, nearly winning a few games. Carlisle suggested his team has struggled to carry that experience over to this season.

“Sometimes it’s hard to remember how hard things were,” Carlisle said. “So that’s where we are now.”

The Pacers appeared to be back in playoff form on Wednesday. Joe Mazzulla credited them with beating his group for most of the match, saying his team was “one step behind in everything.”

“I thought their speed, their pace, they were just a step ahead of us,” Mazzulla said. “It wasn’t our best night. I thought we missed a lot of layups. I thought we had some two-handed rebounds, but we didn’t get them and we tapped them. So we just didn’t play our best and Indiana played great. But there are two things, right? You can focus on that and you can focus on the fact that we just stayed in it. We stayed in it.”

Mazzulla could have cleared his bench at several points in the second half because the game was so lopsided, but he said he never thought about that. Instead, in a sign that the Celtics would do anything to overcome the Pacers’ lead, Tatum started the fourth quarter after playing the entire third quarter. The Celtics were still unable to make up ground on Indiana early in the fourth. Moments after Tatum checked back in for his final stint with 5:17 to go, Boston still trailed by 14 points.

The comeback came abruptly. Derrick White drilled a three-pointer. Brown drove for a dunk. Neemias Queta, who finished the game in place of Al Horford, rewarded Mazzulla’s confidence by grabbing four offensive rebounds in 14 minutes. With less than two minutes remaining, White scored another bucket and then intercepted the ensuing inbound pass. He set up Tatum to pull off a pair of free throws that brought the Celtics within 122-117. On the Pacers next possession, Brown picked Mathurin’s pocket and ran for a breakaway bucket. Still trailing by three points in the final seconds, the Celtics found Tatum for a three-point equalizer.

JT SENDS US TO OVERTIME pic.twitter.com/pKOI3maNV7

— Boston Celtics (@celtics) October 31, 2024

“They weren’t a good fit during the transition,” Tatum said. “I saw they had (Tyrese) Haliburton with me. I understand that this is probably not the match they wanted. Payton (Pritchard) quickly threw it to me. I thought they were going to make a mistake, so I just wanted to shoot quickly. We still had some time left in case I missed getting the rebound or whatever.

After Haliburton missed a long runner at the end of regulation, Tatum celebrated by yelling toward the Boston bench. His team, which had looked dead just minutes earlier, had flown from the grave by erasing a 19-point deficit in the final 7:27. After all the Celtics’ mistakes in the first three quarters, the opportunity to play overtime must have felt like a gift.

They could no longer win there.

“There are two things we need to focus on,” Mazzulla said. “It is ensured that we get out without being half a step behind. But you see what we are capable of at our best from head to toe. And the guys fought, so that was good.”

Despite the late battle, Tatum and Brown knew one good quarter wasn’t enough.

“It starts with us,” Tatum said. “We just have to be better with our energy and try to execute and make the right plays. And not just scoring. We’ve got to be able to get stops, we’ve got to be able to get backs, we’ve got to be able to get guys open. Playing with energy, it’s contagious. And it actually starts with us.”

(Photo of Isaiah Jackson blocking a Jaylen Brown shot during the second half Wednesday night: Marc Lebryk / Imagn Images)