Marcus Morris, Marcus Smart discuss what the Celtics are lacking and how to fix it

After the Celtics coughed up a 28-point lead and lost to the Clippers on Saturday night, forward Marcus Morris launched into a diatribe in which he questioned the team’s attitude and camaraderie while making it clear they all needed to find a way to make this fun again.

On Monday, the team reconvened for the first time since that loss, and as they sat in the film room to watch some of Saturday’s unsightly footage, Morris wanted to be sure his teammates understood why he spoke out. He didn’t think they’d be offended, but he wasn’t sure. And then as he explained himself, it became clear that they actually agreed with him.

“We knew exactly what Morris meant, because we all felt the same thing,” guard Marcus Smart said Monday, sitting on a bench in a quiet corner of the practice facility. “Nobody from the Lakers or Clippers games could sit here and tell you that we gave everything and were fully locked in. We all felt it. Morris was just the one to step up and say something. It was a good thing. We got it. We understood it. We felt it.”

But Morris realized he had not taken accountability for his own slip-ups. So during the film session, he made those clear to his teammates, too.

“I need to be more passionate,” Morris said. “I need to bring my toughness back to the game. Regardless of what’s going on, I still have to be that fiery player to make those fiery plays. Me and Smart. That’s an aspect we bring to this team that’s much needed, and I find myself sometimes forgetting that.

“It’s just something personally I think I’ve been missing the last few weeks, bringing the extra energy, the extra toughness, knocking people on their [butt]. I think that’s a major factor this team has to have to continue to go further.”

On Saturday, Morris said the Celtics’ lack of joy has been apparent for a long time, which seemed a bit surprising considering the Celtics had won 10 of 11 games prior to this recent two-game hiccup. On Monday, though, he clarified that part of his statement.

“A long time is really more like a week,” he said, “But, [expletive], in the NBA world that [expletive] feels like a long time.”

He stood by his general point, however. If these Celtics are to have success, they need to recapture the fun that was more obvious last year, and at some points this season.

“I know it’s a job, but you want to enjoy kicking [butt],” Morris said. “You want to enjoy being up 18 against the Lakers and being up 28 against the Clippers. I want guys to buy in, because you never know. I’ve been in the league eight years, and this is the best shot I’ve had to win a championship.”

Smart said that the lack of fun and joy is inextricably linked to the team’s effort. When one player sees another tussling for a loose ball or diving for a steal, it is contagious. Yes, this is the most talented team Smart has played for, but it takes more than that.

“We all want to win,” Smart said. “It’s just that our effort every single possession of every game isn’t there. And that’s what makes it not fun. As long as we can look ourselves in the mirror and say, ‘I gave it everything I had,’ then the problem is solved. If you look at yourself and, say, ‘I’m not even tired. I could go for a whole other game.’ That’s a problem.”

Smart is defined by his grit and intensity, but he acknowledged that he has not always played as hard as he knows that he can, either. He said that will change.

“I pride myself on leaving it on the floor, but I’ve had moments where I haven’t, where my effort wasn’t up to the standard of me,” he said. “My half-effort compared to somebody else in this league’s full effort might still be better, but for me as an individual, it wasn’t there. Nobody’s perfect. But we’ve just got to make sure we can give everything, every game.”

Smart is the most tenured Celtic, and he has seen this team evolve from a gritty group of overachievers to a talented group that is expected to challenge for an NBA title. But he said that this team cannot lose sight of how it was built.

“We all know, either playing here, or guys who used to play against the Celtics, what this team brings, and that’s toughness,” Smart said. “That’s our identity. We don’t have to talk about it. We just have to go out there and do it, and we haven’t. We have a lot of talented guys that make up for it some games, and some games it bites us in the [butt]. So we have to play our [butts] off. You add effort with the talent we have, and we’ll see what we can do.”

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Celtics point guard Kyrie Irving, who strained his right knee in Saturday’s game, will sit out against the 76ers on Tuesday.

Adam Himmelsbach can be reached at adam.himmelsbach@globe.com. Follow him on Twitter @adamhimmelsbach.