Holiday went 11-for-14 from the field as Boston opened up a 2-0 lead in the best-of-seven series. Tatum finished with 18 points, nine rebounds and 12 assists for the Celtics, who also got 21 points from Jaylen Brown and 18 from Derrick White.

Luka Doncic supplied 32 points, 11 boards and 11 assists for Dallas, which still managed to outshoot Boston 47.5% to 45.2% overall. PJ Washington chipped in 17 points, Kyrie Irving had 16 and Daniel Gafford went for 13.

Game 3 is set for Wednesday in Dallas.

The Mavericks tried to mount a late rally after 3-pointers from Holiday and White on back-to-back possessions put Boston ahead 103-89 with 3 minutes 34 seconds left in the game.

Derrick Jones Jr scored four straight points as part of a 9-0 spurt that ended with a three-point play from Doncic, but Brown’s layup with 29.8 seconds to go dashed any hope Dallas had left.

Dereck Lively II threw home a dunk to get the Mavericks within 63-61 with 7 minutes 30 seconds left in the third quarter, but the Celtics then started to pull away. Boston scored 17 of the next 23 points, with Brown’s trey making it 80-67 with 2 minutes 4 seconds remaining in the period.

Dallas cut its deficit to six before quarter’s end, but Payton Pritchard nailed a 10m 3-pointer at the buzzer to send Boston into the fourth with an 83-74 cushion.

Doncic took over in the first quarter, scoring 13 points to lift Dallas to a 28-25 lead. The Celtics stayed close by going 10-for-10 from the free-throw line through the first 12 minutes of action.

After Doncic canned a fadeaway with 10 minutes 8 seconds left in the second quarter to push the Mavericks’ advantage to 35-29, Boston put together an 11-2 run to go up 40-37.

Neither team led by more than three until Holiday knocked down a triple with 37.1 seconds remaining in the first half to give Boston a five-point edge. Gafford answered with a dunk, forcing the Celtics to settle for a 54-51 lead at the break.