BOSTON — The shorthanded Dallas Mavericks handed the Boston Celtics one of their ugliest losses of the year on Thursday night, staying in command from start to finish in a 127-120 win at TD Garden.

It was another poor performance coming home from a successful road trip. The Celtics have the league’s best road record but continue to struggle at TD Garden, and on Thursday the shorthanded Dallas Mavericks dominated Boston, 127-120, to avenge last month’s loss in Dallas.

The Celtics cut it to 11 at halftime with a couple of late Tatum threes and a buzzer-beating transition layup by White. But the Mavs quickly rebuilt, and then extended their cushion by scoring 10 of the first 12 points of the second half. Dallas topped the 100-point mark before the end of the third quarter and took a 21-point lead into the fourth.