But when he rose up and slammed the ball through the hoop with two hands over LeBron James -- followed by the stare down he gave James, which earned Brown a technical foul -- he provided a fitting exclamation point for Boston's emphatic 139-107 victory over its forever rivals.
"Just being aggressive," Brown said, trying at first to downplay the moment. "I just made a play at the rim."
After a moment, however, he couldn't help himself.
"I ain't gonna lie. It was pretty nice," he added with a smile. "It was pretty awesome."
Brown, who missed the prior two games due to a right thumb sprain, was asked if dunking on James had been on his bucket list.
Again, his smile gave him away.
"I ain't gonna lie. Yeah," Brown said.
The moment encapsulated the way Brown approached the game. From the opening tip and while the Celtics were digging out of an early 8-0 hole, Brown flew around the court. He played with a ton of energy, ensuring that Boston avoided falling into the type of extended first-quarter malaise it has encountered often during a string of six losses in eight games prior to Monday's victory.
But no play among Brown's 20 points, 4 rebounds, 6 assists and 3 steals earned nearly as much emotion -- or excitement -- as his dunk. Like so many other commonalities between Brown and Jayson Tatum, it led to comparisons between Brown's dunk Monday and Tatum's dunk over James in Game 7 of the 2018 Eastern Conference finals.
"That was a helluva play by Jaylen," said Tatum, who finished with a game-high 27 points against the Lakers. "He's so gifted, especially athletically. It surprised me. I didn't think he was going to dunk it, especially that vertical. He's a hell of an athlete, a helluva player."
When asked which dunk was better, Tatum didn't hesitate.
"I'm going to say me," he said.
For his part, Brown agreed.
"I'll give it to him. Yeah," Brown said. "He definitely did in the playoffs, for sure. But just to be out there playing against one of the best players ever to play is an honor. So I always like that matchup. It always gives me a little extra boost."
From the Lakers' perspective, Brown's dunk was one of many things to go wrong for James & Co. on Monday. After watching his son Bronny lose in a high school game in Springfield, Massachusetts, in the afternoon, James returned to Boston and saw his Lakers get pummeled -- after it initially appeared that L.A. would have a field day with its quick start.
The start proved to be the Lakers' high point of the game, one that was all but finished not long after Brown's dunk over James passed through the hoop.
"No," James said when asked if he took the dunk, coupled with Brown's stare down, personally. "Why would I take it personally? You don't take it personal. It's part of basketball. You get blocks, you get dunks, you get crossed over at times. You get stops. Take charges. That's all part of basketball. I think if you were to tally up my successful block attempts compared to my successful dunk-ons, I think I'm kind of [up].
"It's not the first time I've been dunked on, might not be the last time I get dunked on, but Jaylen's been playing extremely well this year, and that was a good play."