WASHINGTON (AFP) — Kristaps Porzingis dazzled in his return from injury and the Boston Celtics dominated on both ends of the floor to beat the Dallas Mavericks, 107-89, in Game 1 of the National Basketball Association Finals on Thursday.

Porzingis missed 10 games after straining his right calf in the first round of the playoffs but made an immediate impact on his return in front of a raucous home crowd.

The Celtics built a 29-point lead in the first half and then thwarted the Mavericks’ third-quarter surge to gain the upper hand in the best-of-seven championship series.

Porzingis came off the bench against his former team and scored 11 points with three rebounds and a pair of big blocks in the first quarter as Boston jumped to a 37-20 lead.

After eight lead changes in little more than six minutes, the Celtics began to impose themselves, pulling away with the help of seven three-pointers in the first quarter alone and keeping up the relentless pace as the Mavs struggled to get their offense firing.

Boston was hot from deep, finishing with 16 three-pointers on a whopping 42 attempts. Jaylen Brown scored 22 points to lead six Celtics players who scored in double figures.

Brown had three of the Celtics’ nine blocked shots and three of their six steals in an outstanding defensive display. Porzingis finished with 20 points and Jayson Tatum scored 16 points with 11 rebounds and five assists.

Dallas star Luka Doncic scored 30 points and grabbed 10 rebounds. But he had just one assist and star teammate Kyrie Irving was limited to 12 points on 6-of-19 shooting.

Still, the Mavs managed to slice the deficit to eight points in the third quarter, only for the Celtics to pull away again.

“Defensively, we made some big-time plays,” Brown said.

“When they cut it to eight, that’s when the game started.”

“I liked how our team responded. We stayed composed. Offensively, we got to our spacing and were able to push that lead back out and make some plays on offense.”

“That was a big third quarter,” he said.

Doncic, who has been playing through a right knee injury and a sore left ankle, struggled to find his shot.

He picked up the pace in the second quarter but Dallas couldn’t find a way to slow the Celtics, who pushed their lead to 29 points, 58-29, on Tatum’s three-pointer with 4:11 left in the first half.