Boston’s Jaylen Brown, center, drives between Washington’s Monte Morris, left, and Rui Hachimura during the Celtics’ 112-94 win Sunday in Boston. Brown had 24 points and 10 rebounds. Steven Senne/Associated Press

BOSTON — Jaylen Brown scored 24 points and the Boston Celtics took advantage of cold shooting by Bradley Beal, routing the Washington Wizards 112-94 on Sunday night.

Jayson Tatum had 23 points, including five 3-pointers, and Malcolm Brogdon added 21 points off the bench to help Boston avoid its third straight loss.

The Celtics connected on 21 3-pointers and had a season-high 29 assists on 36 field goals.

But they were more proud of their defense on a night Washington shot just 38.8% from the field.

“The sole focus is we want to have hot starts like that – offensively and defensively,” Celtics guard Marcus Smart said. “Sustaining it is our problem. We wanted to come out tonight and make a big emphasis on that end. Once we get that lead because of our defense … not to let it slow down and take our foot off the gas pedal.”

Boston interim coach Joe Mazzulla said he was also comfortable with the shot selection on a night his team hoisted 47 3-point attempts.

“I love 3-pointers, I like math,” Mazzulla said. “I think it’s a huge strength of our team. The thing we have to learn on the offensive end … is making sure we’re getting the best, accurate shot every time down and regardless if it goes in or not, it’s a good shot. We did a good job of when shots were not falling of competing defensively.”

Kristaps Porzingis scored 17 points for the Wizards, who have lost three of their last four.

Beal missed his first 11 shots and was scoreless until the third quarter before finishing with 12 points and eight assists. He was 4 of 16 from the field. Beal and Porzingis were the only Wizards starters to reach double figures

“It’s one of those nights where you have three of your five starters really struggle offensively. That’s difficult to overcome,” Wizards Coach Wes Unseld Jr. said.

With Beal struggling, Boston led by as many as 24 points in the opening 24 minutes. Washington’s starting lineup managed to connect on just 11 of its 32 field goal attempts in the half.

Beal’s first points came from the free-throw line with 2:29 left in the third quarter. He didn’t score from the from the field until dropping in a step-back, 17-footer a few possessions later.

It also didn’t help that Sunday was Washington’s second game without one of its peskiest defenders in backup point guard Delon Wright, who could be sidelined up to two months with a hamstring issue.

NOTES

Wizards: The last time Beal was held scoreless in the first half of a game was 2018 against the Golden State Warriors. … The Wizards railed 51-27 in the second quarter before closing the half on a 20-7 run. … Washington has faced first- quarter deficits of at least 15 points in back-to-back games.

Celtics: Grant Williams had 10 points, four rebounds and a block in his first game back from serving a one-game suspension for directing inappropriate language at and bumping into a referee. … Boston led 34-15 at end of first quarter. … The Celtics jumped out to 21-8 lead, with Tatum and Brown taking the team’s first 12 shots and combining for 27 points in the period.