Celtics shouldn’t be satisfied with another lackluster effort in loss to Pacers, despite spirited second half

Celtics coach Joe Mazzulla watched his squad lose its third straight game, and fifth out of its last six.Barry Chin/Globe Staff

Finding encouragement in a spirited and better-than-average second-half performance is not a winning mentality. The Celtics should not walk away the least bit inspired about cutting a 30-point deficit to 5, not a team that was once considered the best in the NBA.

They are, or at least were, better than that. But again they appeared stunned an opponent didn’t fold and stumble back to the locker room once the Celtics got off to a hot start. Boston led, 8-2, and then trailed, 66-36, to the Indiana Pacers, who walked into TD Garden with a losing record and walked out with a 117-112 win.

The Celtics were pathetic in the first half. They lacked effort. They didn’t play hard. They were embarrassing.

“We’ve got to learn how to win again,” said forward Jayson Tatum. “It’s not as simple as that but we’ve got to get back to having fun. We’re playing a little timid, a little tight. Basketball is supposed to be fun.”

Tyrese Haliburton, who, if the Celtics didn’t know before Wednesday, is a pretty good shooter, missed a 3-point shot near the end of the first half. All five Celtics started down the floor for a fast break, except nobody chased the rebound. Haliburton tippy-toed forward to grab his own rebound and then scored a layup and was fouled to put Indiana up 28.

The fans booed, and they should have. This effort was unacceptable. If you’re not going to play well, then at least play hard. Fans who pay their hard-earned money, four days before Christmas, to watch from Section 300 deserve the home team’s best effort.

The Celtics got bullied in the first half, then tried making a remarkable comeback in the second with the grand idea of playing hard on every possession, attempting to challenge Haliburton on 3-point shots, chasing loose balls, defending at the rim.

“I don’t know why we would come out in the first half like that,” Celtics coach Joe Mazzulla said. “We had a choice to make and we made a choice to be better and we have to find a way to not have that anymore.”

Tatum and the Celtics mounted a second-half comeback, but in the end, fell just short.Barry Chin/Globe Staff

And it almost worked, except it didn’t. The Celtics made too many mistakes, even in the second half to complete the rally despite 41 points from Tatum. Haliburton, who scored 33 points, was allowed to shoot threes on a night when he hit six. Orlando’s Paolo Banchero hit six in Sunday’s loss.

Mazzulla has to make better in-game adjustments to combat hot shooters. But that’s not the only thing he needs to improve on.

“Not really concerned about that in a sense it was the first half where we really got outplayed from an effort standpoint,” Mazzulla said. “I’d be more concerned if he didn’t play a completely different style in the second half.

“We just have a choice to make: what team do we want to be? The team that we was the first half or second half?”

Like his predecessor Ime Udoka last season, Mazzulla has no idea how his team is going to play from one game to the next. The Celtics were supposed to be motivated Sunday against Orlando, but they played a below-average game and lost. They were supposed to benefit from a full practice Tuesday and some rest, but the Pacers responded by hitting 15 of 17 shots after starting 1 for 9. Indiana, which entered 24th in the NBA in shooting percentage, scored 71 points in the first half.

What was a minor skid has turned into a reason for concern. The Celtics did show signs of escaping their offensive doldrums with a 69-point second half, but then again it came against a relaxed defense that was playing with a 20-plus point lead.

The entire team is slumping offensively and the missed shots are discouraging the players and affecting the defense. Wednesday was the worst performance of the season because the Celtics didn’t give 100 percent, not even close. And when they did in the second half, the Pacers got every break and made every pivotal shot.

That’s just plain karma. The Celtics didn’t deserve to win. And they shouldn’t walk away the least bit proud of their second-half effort. Even bad teams are capable of runs in the NBA, so what the Celtics did wasn’t impressive.

They played hard. They actually tried. Hooray for that.

Mazzulla again played Joe Cool. It’s not that he doesn’t play tough cop or disciplinarian at times, but he has taken this losing streak rather matter-of-factly. It is December and every team slumps, but consecutive losses to Orlando and then falling behind by 30 to Indiana indicates this is more than a normal skid. The Celtics aren’t giving full effort at all times and that should be a prerequisite for stepping on the floor.

There were some highlights for the Celtics Wednesday, like this drive-and-dunk by Jaylen Brown early in the first quarter. Barry Chin/Globe Staff

“I don’t get concerned; you have to rely on who our guys are as people,” Mazzulla said. “And you have to rely on the process of what we’re trying to build. And a half like this, I would be more concerned if it was two halves, but it was one. And we’re not playing well. Moments like this I think it’s important to trust your guys. They’ve been through a lot. They’ve had games like this and they’ve bounced back. I’m not concerned that I’m not going to know what team is coming in. I’m OK with I know the guys as people.”

So the Celtics should be less disappointed because they were only half terrible? That’s not a winning mentality.