**BOSTON (AP)** — Jaylen Brown scored 22 points, and Kristaps Porzingis added 20 in his first game in over a month as the Boston Celtics defeated the Dallas Mavericks 107-89 on Thursday night in Game 1 of the NBA Finals.

Derrick White contributed 15 points for Boston, which led by 29 points in the first half and made 16 three-pointers in a strong start to their quest for an 18th NBA title.

Porzingis, who had been sidelined since April 29 with a strained right calf, came off the bench and provided an immediate spark, adding six rebounds and three blocks in 21 minutes.

Six Celtics players scored in double figures.

Luka Doncic led Dallas with 30 points, and P.

J.

Washington added 14 points and eight rebounds.

However, Dallas struggled with offensive consistency beyond that, totaling just nine assists on its 35 field goals for the game.

Former Celtic Kyrie Irving had a tough game, finishing with 12 points.

He received a loud and extended chorus of boos when he was introduced before the game, which continued whenever he touched the ball.

This treatment came after Irving had sparred with Boston fans and was fined for using an obscene gesture during a 2022 playoff visit to TD Garden.

The Celtics, seeking their first championship since 2008, showed little rust from their 10-day layoff after sweeping the Indiana Pacers in the Eastern Conference finals.

They played with energy throughout, sharing the ball in the half-court and getting it to shooters for open three-pointers.

They also attacked the interior of the Dallas defense and got to the rim for several dunks.

Apart from Doncic, who shot 12 of 26 from the field, Dallas struggled early to get into its sets and couldn’t find a consistent offensive rhythm.

The Mavericks led by one point midway through the first quarter.

The Celtics responded by outscoring them 44-16 to make it 58-29 in the second quarter.

Things changed over the next 12 minutes of game action when Dallas used a 35-14 run, including 15 points by Doncic, to cut Boston’s lead to 72-64.

But Boston ended the third quarter with a 14-2 spurt to push the lead back up to 86-66 entering the fourth quarter.

Dallas had just five assists through the first three quarters, the fewest any NBA team has had in any game through 36 minutes in the last three seasons.

Porzingis ended his 10-game hiatus when he came off the bench with 7:17 left in the first quarter in place of starter Al Horford.

With the exception of a white compression sleeve on his right leg, it was hard to tell Porzingis was coming off an injury.

He got into the mix quickly, knocking down a pair of free throws after being fouled by Doncic.

A possession later, the Latvian connected on his first field goal with a short jumper over Doncic.

Minutes later, he got loose in the paint for a two-handed dunk over Derrick Lively.

On Dallas’ next possession, Porzingis was there to swat away Jaden Hardy’s layup attempt.

The Celtics pushed the ball up the court and got it back to their big man, who calmly buried a 16-footer.

It was part of a 17-5 surge by Boston over the final 5:24 of the quarter that saw Porzingis go 4 for 5 from the field, score 11 points, block two shots, and grab three rebounds.

Boston carried a 37-20 lead into the second quarter.