Jaylen Brown focused on control and defensive discipline after the Boston Celtics opened their playoff series with a 123-91 win over the Philadelphia 76ers on Sunday.

“The game is just about managing your emotions… they’re going to go on runs, we’re going to go on runs,” Brown said. “We just got to cut out the momentum plays.”

A key sequence in the third quarter highlighted that approach, as Boston halted a potential Philadelphia push with a steal and back-to-back three-pointers.

“They were trying to get out and get a transition basket and we was able to stop it,” Brown said. “That’s just going to be how the series is going to be… we got to just manage momentum.”

Boston never trailed and built a lead as large as 35 points, shooting 50% from the field and hitting 16 three-pointers.

“That was Celtic basketball,” Brown said. “We’ve been a harder playing team all year. That can’t change now that the playoffs have started.”

The All-Star wing emphasized that defense will define the series more than scoring.

“Our offense can’t win us this series… our offense is important, but we got to make sure we guard,” he said. “I think tonight we did a great job.”

Philadelphia shot 39% overall and just 4-of-23 from beyond the arc, struggling to generate efficient looks.

Brown also pointed to the importance of leadership with several teammates making their playoff debuts.

“Just breathe… manage your emotions,” he said of his message. “Stay together, win the fight, be the harder playing team and guard.”

Boston’s depth was evident with 12 players seeing action, including Neemias Queta, who scored 13 points in his first playoff start.

“Just growth… being big at the rim, protecting us,” Brown said. “We need him on the floor.”

Brown himself finished with 26 points on 11-of-21 shooting, finding rhythm as the game progressed.

“Just taking my time, getting to my spots, letting the game kind of flow,” he said. “When the game will open up… you just got to be ready for it.”

The Celtics star also addressed the team’s mindset entering the postseason after a week off.

“We’re ready. We’re prepared,” Brown said. “We just got to be ready every time we step out on the floor.”

Despite the dominant margin, he downplayed the significance of one result in a seven-game series.

“It’s one game… we got to continue to play well and play physical on the other end,” Brown said.

Brown added that playoff intensity requires an elevated version of the team’s regular-season identity.

“Our standard is being the harder playing team… as the playoffs teams play harder, we got to play even harder,” he said. “The mentality, the focus, the attention span… needs to improve.”

The performance marked the largest margin of victory in a Game 1 at home in franchise playoff history.

“For us to have the biggest margin… is great,” Brown said. “It sets the tone and it reflects our focus and our intensity.”

Still, Brown kept the message grounded heading into Game 2.

“Nothing is guaranteed… we just got to come out and play and earn it,” he said.