BOSTON — Montrezl Harrell took his time flexing before he stepped to the free throw line Wednesday night. The Washington Wizards center had just driven to the basket for an aggressive layup and drew a foul that would earn him his 20th point midway through the third quarter. He brought his fists slowly toward his shoulders, savoring the moment.

The Boston Celtics were unable to contain Washington’s fiery backup all night as he led the Wizards to a 116-107 win, but Harrell’s contributions — a game-high 25 points and 11 rebounds — were especially needed in the second half.

Starter Daniel Gafford left with a right quadriceps contusion in the second quarter, an injury that looked far more damaging when Gafford lay on the ground, rocking back and forth in pain, after he collided with the Celtics’ Jaylen Brown. The big man barely put any weight on the leg as he was helped off the court, leaving Harrell as Washington’s only true center. Last year’s starter, Thomas Bryant, is still recovering from an ACL injury and is not expected back until December at the earliest.

“My team feeds off me, man,” Harrell said. “I play with a lot of passion, I play with a lot of heart, I play with a lot of aggression, man, and it’s all generated in the right way, and I think my team does a great job of understanding that.”

Without Gafford, the Wizards (3-1) weathered a second-half push from the Celtics, with Harrell occasionally spending time at power forward and forward Davis Bertans filling in at center, leaving Washington particularly vulnerable at the rim.

Boston (2-3) made the Wizards pay, racking up points in the paint in the third. Yet despite a quick 7-0 run that got Boston within three points late in the fourth quarter, the Wizards were quicker to the ball all night. They turned even the sloppiest of possessions into buckets down the stretch to seal the win.

Here’s what you need to know about Wednesday’s win:

Unseld remembers Ferry

Former Washington general manager Bob Ferry died Wednesday at 84, news Wizards Coach Wes Unseld Jr. learned just before he addressed reporters in his pregame news conference.

Ferry was one of the league’s most accomplished general managers. He played five seasons with the organization, then based in Baltimore, before spending 17 years running the front office, making 13 playoff appearances. The Bullets won the 1978 NBA championship, and Ferry twice was named executive of the year.

He also was the league’s second general manager, following Red Auerbach, to hire two Black head coaches: Ferry picked Unseld’s father for the job 15 years after hiring K.C. Jones.

Unseld’s warmest memories are not of Ferry the basketball mind but Ferry the family man.

“He was in the front office when my father was a player, so we spent quite a bit of time with him and his family; [son] Danny was in our house quite often. My mom oftentimes babysat him and his brother, Bobby, so it was kind of a generational thing,” Unseld said. “When I was in high school, I’d work out with Danny when he was at Duke, and he would intentionally try to just crush me.

“A lot of fond memories. I really feel awful; it kind of just threw me for a loop just moments ago when I found out before coming in here. … I know how difficult this time is, so I just want to let them know we’re thinking about them, we care for them, and we’ll be there for them.”

Role players step up

Unseld has been trying to get starting guard Kentavious Caldwell-Pope more involved in the offense after a quiet first few games.

Caldwell-Pope responded with his best performance of the young season Wednesday, harassing Celtics star Jayson Tatum on defense and hitting big three-pointers at critical junctures. Caldwell-Pope had 11 points, but his offensive contributions were more impactful because of their timing — which is how starting forward Kyle Kuzma made his mark, too. He was similarly solid on defense and added 12 points, eight rebounds and two assists.

“You don’t want [Tatum] to get the ball and then start getting comfortable with it, get in his rhythm,” Caldwell-Pope said. “So I try to keep him as uncomfortable as possible throughout the game. Show him different coverage. … I might face guard him a couple times, just show him some different looks just to keep him thinking about what I’m going to do. It worked tonight, and it’s always good to get your work in early on guys like that.”

A large part of Kuzma’s and Caldwell-Pope’s big nights was tied to Bradley Beal’s lack of impact as a scorer. With backup guard Raul Neto out with a shoulder contusion, Unseld wanted to use Beal more as a playmaker, but the all-star uncharacteristically faded into the background. He had 17 points on 7-for-25 shooting, including 0 for 6 from three, and 10 rebounds. He turned the ball over five times.

“My thing is the defensive end. Keep defending,” Unseld said of Beal’s performance. “You’re going to make shots. Your rhythm will come. He’s not forcing shots. He’s taking shots. … He’s trying to play the right way. He hasn’t made a lot of [shots] yet, but at some point that dam will break.”

Neto is day-to-day

Neto looked to be in considerable pain when he left in the fourth quarter of the Wizards’ loss at the Brooklyn Nets on Monday. In a relief to his coach, he was diagnosed with only a left shoulder contusion. He was able to participate in the Wizards’ shoot-around Wednesday morning, but they held him out of action against the Celtics anyway.

“He got all the tests, required tests,” Unseld said when asked whether Neto had undergone an MRI exam. “He’s done some strength work, gotten treatment multiple times. He’s just not where we want him to be, [where we] feel comfortable with him being out there. So right now we’ll hold him out today, see how he responds tonight and into tomorrow morning.”