J.R. Smith said superstar LeBron James needs support from his team-mates as the Cleveland Cavaliers fight to overturn a 2-0 series deficit in the NBA Eastern Conference finals.

James posted a triple-double with 42 points, 10 rebounds and 12 assists, but the Cavaliers still lost 107-94 to the in-form Boston Celtics on Tuesday.

Smith and fellow guard George Hill were outscored by Boston's backcourt 41-3 in game two at TD Garden.

"We're making Bron play hero ball, which is tough to do, especially in the Eastern Conference finals," Smith told reporters.

"We got to help him. With that said, we have to give him an opportunity to make him feel confident to give us the ball so we can make the right plays. We got to help him and he's got to help us."

Hill added: "I'm trying to figure it out myself. I think a little bit of just trying to be more involved offensively, trying to be more involved defensively, not waiting until a play is possibly called and things like that to go do it.

"Make some things happen defensively where I can get active and get some easy baskets or crash the boards and taking it coast to coast and things like that.

"I've just got to be more assertive, I've got to play with that edge like I did in the second series and things like that."

James has scored 40 points five times this postseason. Normally those performances mean wins for the Cavaliers. In fact, Cleveland were 4-0 when he scored at least 40 before Tuesday's loss to the Celtics.

However, in those games Smith and Hill combined to average more than 15 points.

While the onus does not entirely fall on these two guards, they know the better they play, the easier they make things on James.

Smith was the first to admit he needs to be better and Hill knows for the Cavaliers to win, he has to contribute.

"There's no one to blame but myself," Hill said. "You've got to look yourself in the mirror and say, 'What can I do better?'"