Bam Adebayo took the blame for the Miami Heat's Game 5 defeat to the Boston Celtics on Friday, though Jimmy Butler did not agree with his assessment.

The Heat failed to close out the Eastern Conference finals as they blew a 12-point lead to lose 121-108, meaning their series advantage was cut to 3-2 ahead of Game 6 on Sunday.

Adebayo, who played with a sleeve on his left arm after supposedly suffering an injury late in Game 4, contributed 13 points on 5-for-11 shooting, eight rebounds and eight assists but felt he lacked intensity on the defensive end.

"I played like s***. Bottom line. I put that game on me. It's not my team-mates' fault, it's not my coaches' fault, it's me. I missed too many shots I should have made. Put that one on me," said Adebayo.

"I wasn't being the defensive anchor that I should have been. I don't think I was communicating fast enough. I feel like I was a step behind today.

"I got to be better. That's the bottom line. That's it. There's no excuses to this ... this game is on me. I played terrible and that can't happen."

Butler insisted the defeat was "on everybody" and said he would attempt to lift Adebayo's spirits ahead of Game 6. 

"It's not [on Adebayo]. It's on everybody. He does so much for us that it could feel like that at times, but it's definitely not on him. It's on us as a whole," said Butler. 

"We all understand that because nobody was playing the way we're supposed to play, the way we have to play in order for us to win. Nobody. And for him to say that, I respect it, I love him for it. But he can't do it by himself – we've got to be there with him. 

"I will [speak to him] but I think he knows you can't get stuck on this game now. We learn from it, it's something of the past. But we're going to need him to be who he is on Sunday. 

"We need everybody to be that way. We're gonna watch film, we're gonna learn from it, not saying we already don't know what went wrong, but we'll be ready to go. We will fix it."