The Celtics moved to 13-8 on the season but still have some work to do in the NBA Cup, where they are in second place at 2-1 in Eastern Conference Group C behind the Atlanta Hawks.
After their celebratory trip to the White House on Thursday, the Celtics trailed by two at half-time, having been 11 points behind at one stage, and it wasn't until late in the fourth quarter that they were able to pull away from the Wizards.
Brown delivered down the stretch, his superb turnaround jumper giving Boston a 99-92 lead and ending Washington's resistance.
It was far from a vintage Celtics performance though.
Jayson Tatum, who scored 16 points, was 0-for-10 from three-point range and Boston shot 42.4 percent from the floor and 23.9 percent from three-point range, equalling their lowest scoring output of the season.
Celtics coach Joe Mazzulla picked up a technical foul in the second half for remonstrating with the referee but said his emotions had an impact on the game.
"It changed the energy in the arena. Did you feel that? It wasn't really about energizing the guys, it was more about manipulating the environment. It was just what the environment needed at the time," said Mazzulla.
The Dallas Mavericks, without the injured Luka Doncic, survived a strong comeback from the Denver Nuggets to emerge with a 123-120 win.
Naji Marshall top-scored for the Mavs, off the bench, with 26 points, while P.J. Washington put up 22 points.
Nikola Jokic had a triple-double, top-scoring for Denver with 33 points along with 17 rebounds and 10 assists.
Dallas had a 24-point lead early in the third but Denver battled back and DeAndre Jordan's alley oop dunk shot made it a two-point game with 8:47 left in the fourth.
Daniel Gafford's two-point shot levelled the game 108-108 with 5:13 remaining and it was nip and tuck all the way down the stretch.
With Denver down a point and just four seconds left on the clock, Jamal Murray tried to hit the rim with his second free throw but inadvertently found the basket and two free throws from Washington sealed the win for Dallas.
"We all stepped up at the right time and we gutted out this win," said Mavs point guard Kyrie Irving, who said the team had shown the right attitude without Doncic.
"It is next-man-up mentality and we've got to do our best to find that rhythm. Consistently feed each other that confidence, especially in tough environments like this. We had to will ourselves to this win," he said.
Walking with confidence
The Philadelphia 76ers snapped a five-game losing streak with a 113-98 win over the Brooklyn Nets.
Jared McCain scored 30 points and Tyrese Maxey 26 as the 76ers coped without the injured Joel Embiid and Paul George.
Cameron Johnson top-scored for the Nets with 37 points.
Andrew Wiggins scored 30 points for the Golden State Warriors as they won 112-108 at New Orleans.
A pair of free throws from Draymond Green saw the Warriors over the line.
Golden State's win moves them to 12-3 in the regular season and put them into the quarter-finals of the NBA Cup as they sit on a 3-0 record.
Giannis Antetokounmpo produced his second triple-double in four games putting up 37 points, 11 assists and 10 rebounds as the Milwaukee Bucks beat the Indiana Pacers 129-117.
Damian Lillard helped out with 24 points and 12 assists as the Bucks claimed their third straight win and went 2-0 in the NBA Cup.
Gary Trent Jr, off the bench, added 18 points for Milwaukee with his 6-of-10 three-point shooting.
"He's playing with confidence, walks with confidence, works hard," Antetokounmpo said.
"Those are the shots he makes in practice and we knew that sooner or later he would make them in games.
"I am happy for him and need him to keep playing with confidence."
