BOSTON — The Boston Celtics did not deal with much adversity during their run to the championship last season, especially in the regular season. Despite a similar start this season (Boston was 24-6 through 30 games last year and is 22-8 this season), the product looks different. After a 118-114 loss to the 76ers on Christmas Day at TD Garden, Boston already has more losses at home (five) than it did all of last season.

Boston has lost two straight games for the first time this season and fell to 3-4 in its last seven games. That type of slump is not cause for alarm on the surface, but how the Celtics have lost of late is troublesome. They lost at home to an under-.500 Bulls team on Dec. 19, fell to the heavily undermanned Magic on Monday, then had a defensive stinker against Philadelphia on Wednesday.

Some nights, the offense has been bad (Monday), but others nights, like Wednesday, the defense has let the team down. That type of play led Celtics coach Joe Mazzulla to speak some rare words about his team.

“We’re playing inconsistent basketball, so we’ve got to be better at both ends of the floor,” Mazzulla said. “Got to be more consistent at both ends of the floor.”

The consistency woes can be attributed to a few issues. For one, health remains a question mark. Guard Jrue Holiday missed Wednesday’s game because of a shoulder injury and center Kristaps Porzingis was sidelined at halftime because of a sore ankle. Those absences left the Celtics vulnerable against a Sixers squad that was close to full strength.

“We got to just take a look at it,” forward Jaylen Brown said. “It feels that way, but it always feels a little bit worse than what it actually is. We got some different guys in the lineup and stuff like that. So I feel like we haven’t had as much continuity as we would like when we’ve been out there. So we’ll just take a look at it, and it’s a moment where we can improve as a team.”

Celtics center Al Horford indicated that Boston’s recent woes went beyond some continuity issues when asked about Mazzulla’s assessment.

‘I think that’s a fair criticism from him,” Horford said. “I just think that we have to really dive into our work a little more and understand that we can’t relax during periods of the game, no matter the circumstance. We have to make sure that we’re a little better in that regard, and with this group, I know that we’re capable of getting it together. Now, we have to look at this opportunity to play Indiana and come out and have a better performance with the effort and the intensity that it requires.”

The challenge for the Celtics in the coming days and weeks is they don’t have much time to fix any on-court issues in practice. Boston plays every other day for the next three weeks, with a couple back-to-backs mixed in. With tougher opponents coming up, starting with the Pacers on Friday night, the Celtics will need to improve quickly to avoid falling down the East standings.

“We’ve got to be better,” forward Jayson Tatum said. “It’s still a long season. Nobody’s panicking. We’ve got to navigate the emotional roller coaster of the NBA season. It feels a lot worse than it actually is. We’re not panicking or anything. We’ve just got to man up and look in the mirror and figure out some things that we’ve got to do better at.

“Everybody’s fully capable, and we’ve always done a really good job of responding, and I have no doubt that we will. So I’m not panicking, but we’ve got to be better, and we will.”