BOSTON (AP) – Marcus Smart scored 20 of his 22 points in the second half, and the Boston Celtics beat the Oklahoma City Thunder 126-122 on Monday night for their seventh straight win.

Boston trailed by as many as 15 in the third quarter, but it outscored Oklahoma City 37-26 in the fourth.

Jayson Tatum had 27 points and 10 rebounds for the Celtics. Jaylen Brown scored 26, and Al Horford added 12 points and 11 rebounds.

Smart also had eight assists and five rebounds and reserve Payton Pritchard added 10 points, leading a key surge late in the third and early in the fourth as the Celtics rallied.

Shai Gilgeous-Alexander led the Thunder with 37 points. Lu Dort scored 21 and Aleksej Pokusevski finished with 16 points and 14 rebounds.

All five starters scored in double figures for Oklahoma City, which couldn’t hang on after a strong first half.

The Thunder had just six turnovers in the first half, but seven in each of the final two quarters while falling to 2-5 on the road.

Pritchard hit a 31-foot 3-pointer with the shot clock about to expire late in the third, pulling Boston within nine. Pritchard then had a steal and a layup just before the buzzer, cutting the margin to 96-89 entering the final quarter.

Pritchard hit another 3-pointer in the opening minute of the fourth and Oklahoma City’s 15-point lead was down to 99-94 with 11:11 left.

Smart drew an offensive foul on Gilgeous-Alexander and a two-handed dunk by Tatum tied it at 107 as fans roared in approval of Boston’s surging momentum.

A three-point play by Dort tied it at 115 with 2:41 left, but Smart hit a 3-pointer to put Boston back up and Derrick White followed with another 3 after a miss by the Thunder at the other end. Boston led the rest of the way.

TIP-INS

Thunder: Outrebounded Boston 51-46. … Oklahoma City was playing the second of a four-game trip with stops still to go in Washington and Memphis.

Celtics: G Malcolm Brogdon missed his third straight game with a tight right hamstring. … F Grant Williams received a technical foul with 7:31 left in the first quarter after complaining about a no-call when he went up for an offensive rebound. … Tatum received a technical 1:04 into the second quarter after a foul, although he appeared to be yelling at himself. … Boston Bruins winger David Pastrnak received a round of applause when he was shown sitting courtside during a stoppage in the second quarter.

UP NEXT

Thunder: Visit the Washington Wizards on Wednesday night.

Celtics: Visit the Atlanta Hawks on Wednesday night.