The Dallas Mavericks were just a minor distraction to the Boston Celtics in their pursuit of banner 18.

The Celtics opened a 21-point halftime lead Monday and rolled to an 106-88 victory over the Mavericks in the deciding Game 5 of the NBA Finals before a celebratory crowd at the TD Garden.

The Mavericks displayed little of the execution and urgency they showed in Friday night’s 122-84 blowout victory in Game 4 at the American Airlines Center. Most of that was the Celtics’ doing. The Mavericks shot 44.9% from the floor, hit 11-of-37 from downtown with 35 rebounds and 18 assists. Dallas first team NBA All-Star Luka Doncic finished with 28 points and 12 boards, but was 2-of-9 from behind the arc.

“They just came out aggressive and they were good defensively and they are a great defensive team,” said Mavericks guard Josh Green. “I have respect for them and respect for their coaches and their great defensive team.

“I think we got here and everyone is hungry now and obviously we didn’t get what we wanted. We need to regroup and be back here again next year. That’s the goal every single year.”

The Mavericks were like a top contender that suffered a humbling middle-round TKO in a championship fight against a merciless title holder. Their only hope for redemption lies in a rematch against the Celtics in the 2025 NBA Finals.

“They have a great team and they have been together for a long time,” said Doncic. “They had to go through everything so we have to look at them and see how they play and their maturity.

“They have great players and we can learn from that and we have to fight next season. I feel great about (the future), we made some great moves and I would say we have been together for five months. I am proud of every guys who stepped on the floor, all the coaches and all the people behind us.

“Obviously we didn’t win finals but we had a hell of a season and I am very proud of all of them.”

Doncic’s night did not get off to a good start on three fronts. In the opening 65 seconds, Doncic had an open 3-point shot from the top of the key rim out, he picked up his first foul blocking Jaylen Brown on the baseline and had his pocket picked from behind by Derrick White in the Boston end.

“I was out there trying to play but I didn’t do enough,” said Doncic.

Doncic scored his first points converting a 3-point play that made it 9-5 with 7:03 to play. The Maverick never led in the first but cut it to 19-10 on a Dante Exum bomb from 26-feet with 1:55 to play. Boston closed the quarter with a 9-0 run to go up 28-18.

The Celtics continued to extend their lead early in the second, but the Mavs showed some fight when P.J. Washington hurled the much larger Kristaps Porzingis to the floor at 9:32. A brief stare-down in the paint was all that came of it. Celtics guard Peyton Pritchard’s 49-foot trifecta at the buzzer ended a 19-7 run that put Boston up 67-46 at the half.

“It was just everything and that is what they do,” said Doncic.

Complacency never took hold in the Celtics’ locker room during the break. The Celtics opened the third with an 11-4 run prompting Kidd to call timeout. The most humiliating moment of the frame was when Doncic launched a 3-point airball with 2:27 to play. Boston led 86-67 after three and the fourth quarter was just a formality before the coronation.