John Wall, right, sat next to Bradley Beal for the final minutes against Boston on Saturday, offering pointers. (Jonathan Newton/THE WASHINGTON POST)

Bradley Beal’s stone face and steely eyes couldn’t mask the anger and melancholy festering inside him as he trudged toward the locker room Saturday after his disappointing home debut against the Boston Celtics.

Noticing that Beal was rattled, Washington Wizards assistant Sam Cassell felt compelled to comfort the 19-year-old rookie who scored just two points, missed all five of his shots and watched the final 4 minutes 52 seconds of an 89-86 loss unfold from the bench.

“This is only your second game and you’re starting in the NBA, as a 19-year-old,” Beal recalls Cassell telling him. “That has to make you proud in some way.”

Beal didn’t fully process what Cassell was trying to say until several hours later. Because immediately after the game, Beal chewed himself out harder than the handfuls of Skittles that he plowed through while getting dressed in front of his locker room stall. Beal remains his harshest critic but has a greater perspective.

LeBron James, Dwight Howard, Andrew Bynum, Darius Miles, Kevin Durant and Michael Kidd-Gilchrist are the only players in NBA history to have started the season opener for their teams at a younger age than Beal, who was 19 years 124 days old when he started at shooting guard and scored eight points in the Wizards’ loss in Cleveland last week.

“I don’t use age or being a rookie as an excuse. But it is a great honor, honestly. Not a lot of people are in the position that I’m in,” said Beal, the third overall pick out of Florida last June who is averaging five points and shooting just 15.4 percent in his first two games. “I’m fortunate. But at the same time, I have to take advantage and prove myself still. I just can’t take anything for granted.”

Beal didn’t realize how lethargic he appeared until he watched film of his performance and had Coach Randy Wittman break down his mistakes.

Center Emeka Okafor blocked a shot and Beal recovered the ball, only to dribble down the floor and quickly pulled up for a jumper when a drive for a higher-percentage or simply setting up a play would’ve been a better alternative.

Beal also saw a player who was standing upright, passively waiting for the game to come to him, and not one with his head lowered, ready to attack with purpose. More importantly, Beal saw a player who wasn’t enjoying himself.

“I think I’m losing sight of what’s important, which is having fun,” Beal said. “I always had fun. Laughing on the court and having a blast, but I haven’t been doing that the last two games because I’ve been distracted with other things. I’ve turned it around mentally and I just looked myself in the mirror. I’m the one who has the change. I mean, it’s nobody else’s fault but mine.”

In his first two games, Beal has missed 11 of 13 shots, including his past nine overall. He also hasn’t made a shot since connecting on his first two three-point attempts in the first quarter in Cleveland.

Beal hasn’t been very aggressive since the third quarter of that game, when he tried to break down Cavaliers rookie Dion Waiters off the dribble and lost the ball, leading to a breakaway dunk on the other end and a quick hook from Wittman.

Wittman stays on Beal, taking him to task for losing focus, and has even stopped practice to single him out for failing to get back on defense.

“Coach is on my butt all the time, because he knows I can be good,” Beal said. “He knows I can be better and he knows I can accept his criticism and I just have to take it and run with it. And just keep being aggressive and doing what he wants me to do.”

The Wizards (0-2) started training camp without John Wall and Nene and they may also be without Jordan Crawford for their rematch on Wednesday in Boston.

Crawford scored 21 points before spraining his left ankle in the fourth quarter last Saturday and will be a game-time decision. He lost out on the starting shooting guard job to Beal but has led the team in scoring in each of the first two games, taking the opposite approach from Beal by looking to immediately provide an offensive boost.

“It’s not really his game to force it. He likes to let the game come to him,” Crawford said, “but as a two-guard in this league, you’ve got to be aggressive and bring some of the attention to you on defense and that opens it up for other players.”

Beal will likely need to do more for the Wizards to have success against the Celtics but Wittman doesn’t want him to limit his focus to shooting the ball, noting how Beal had just one rebound in the last game.

“Bradley’s playing with no rhythm to his game and he’s got to do other things,” Wittman said.

Beal’s teammates have tried to offer words of encouragement to remind him of the difficult adjustment that rookies have in the NBA. Wall, who made his debut at age 20, offered pointers as he sat next to Beal for much of the game against Boston.

“He’s a rook. His whole season is going to be trying to figure it out,” said Okafor, the 2005 NBA rookie of the year. “He’s going to get down, because he’s going to try to do well all the time. He’ll learn that you can’t, and just give a good effort. You can’t get too high. You can’t get to low in this league. You’ve just got to keep an even keel and keep moving.”

The slow start has created other challenges for Beal, with his inbox, voicemail and text messages all featuring tips from wanna-be experts, telling how to fix the problems.

“You always have people who think they know the answers to everything. People are texting me, calling me. ‘Oh you’ve got to do this.’ ‘You’ve got to do that,’ ” Beal said. “I have too many people in my ear. So I have to eliminate that and keep my circle small.

“We’re trying to get wins here,” Beal said. “We’re 0-2. We have to figure out how to get wins and the outside people can stay on the outside.”