Brad Stevens explains how LeBron James has become a better player since he arrived in the league as the Celtics coach. Stevens also adds that he may look to double team LeBron in order to try and stop the Cavaliers. (1:45)

BOSTON -- After watching Cleveland Cavaliers star LeBron James shred his team's defense during Game 1 of the Eastern Conference finals, Boston Celtics coach Brad Stevens said James has continued to improve his play in recent years and that there are no obvious answers to how he can be slowed.

James erupted for 38 points on 14-of-24 shooting and added nine rebounds and seven assists in 42 minutes of play during Cleveland's 117-104 win at TD Garden. He accounted for 55 of the 105 points the Cavaliers put up while he was on the court, either by scoring or dishing assists.

The Celtics couldn't slow James when he attacked the basket. He generated a postseason career-high 26 points in the paint and, according to ESPN Stats and Info, shot 81.2 percent in the paint. Twenty of those points in the paint came in the first half, when the Cavaliers built a comfortable lead.

"[James] made it clear -- it was very clear -- that he was trying to get to the rim on us no matter who was on him," Stevens said.

Celtics forward Jae Crowder said Boston needs to do a better job of making James think twice before driving.

"Obviously, he's a great scorer, and when he gets going downhill, he just has to see bodies," Crowder said. "I have to do a better job of being up to touch on him, being on the ball, making it tough for him. But he has to see bodies behind me. We have to do a better job of showing help early, then getting out and spreading out to the shooters so they won't be a factor in the game.

"We'll watch film and try to adjust to it and give him a different look, obviously. He got comfortable with what we were doing on the defensive end, and he had his way. So we've got to switch it up and come with a different game plan."

LeBron James scored 38 points in Game 1, including a postseason career-high 26 points in the paint. Charles Krupa/AP Photo

The Celtics tried multiple defenders on James throughout the night, including big men Al Horford and Kelly Olynyk. Boston received some of its most inspired defense against James from rookie Jaylen Brown, who suggested he wasn't overwhelmed by going against a star like James.

"It was just playing basketball," Brown said. "He laces his shoes up like I lace mine up. Coming out, playing basketball and trying to make it tough for him. I feel that's my job."

Told that Horford had suggested Brown might deserve more playing time moving forward, Brown said he'd be ready for anything.

"If Coach tells me, I'm going to be ready to guard whoever," Brown said. "If it's the waterboy, I'm guarding him, too. It doesn't matter to me."

James did much of his damage Wednesday night working against single coverage. Stevens admitted that Boston might have to consider more double teams, as risky as that can be against Cleveland.

"Doubling is really scary against these guys, but it may be necessary," Stevens said. "The conundrum is, do you double and risk giving up those easy step-in 3s and the rebounds? Or do you try to stay at home and do the best you can and make them make a tough shot? It's all easier said than done, but we've got to figure out our best avenue quickly."

Stevens and Crowder noted how James' high basketball IQ and court vision make him especially dangerous to stop, particularly when he generates open looks for teammates. Kevin Love finished with 32 points on 9-of-16 shooting, including six 3-pointers.

"I've always been so impressed with his mental understanding of the game and the way that he communicates and his insights and the way that he reads defense and offense and everything else," Stevens said. "He's always picking the matchup that he wants. I just said in the coaches' meeting right before we left: It's hard to believe, but he's better than when I got into the league. A lot better. Just as you get older, you gain more experiences, you see more things.

"I didn't think he could get any better after that, but he is. He's a good player. Great player."

The scary part for Boston is that James suggested the Cavaliers might be capable of an even better performance.

Said James: "I don't even think we played that great tonight."