PHILADELPHIA — Guard Isaiah Thomas scored 13 of his 20 points in the decisive third quarter as the Boston Celtics beat up the Philadelphia 76ers 112-92 Sunday night.

The game was rescheduled from Saturday because of a snowstorm.

Forward Jae Crowder also finished with 20 points for Boston, which won its second straight and extended its winning streak over Philadelphia to seven games. Guard Avery Bradley had 19, and guard Marcus Smart contributed 16 off the bench for the Celtics (24-21).

Forward Robert Covington notched 25 points to pace Philadelphia, the NBA’s worst team (6-39). The Sixers were seeking to win consecutive games for the first time since March, but they turned the ball over 24 times, seven more than their league-worst average and the most they have had in their last 18 games.

The giveaways resulted in 25 points by the Celtics, who began the night forcing 17.9 turnovers a game, the league’s second-highest total.

Nine of those Sixers turnovers came in the third quarter, when Boston outscored Philadelphia 36-26.

Boston shot 11-for-25 from 3-point range in the game. Crowder was 4-for-6, while Bradley went 3-for-4 and Smart 3-for-6. Philadelphia made only eight of 26 long-range attempts.

The Celtics built a 58-43 halftime cushion after outscoring the Sixers 31-18 over the last 13 minutes of the first half. Thomas and Bradley combined for 12 points as Boston opened the third quarter with a 22-8 flurry. Crowder capped it with a three-point play with 6:07 remaining in the period, making it 80-51.

The Sixers were never closer than 16 the rest of the game.

Boston, up 27-25 late in the first quarter, went on a 24-8 run to take a 51-33 lead with 6:33 left in the half. Crowder and Smart combined for the last 17 points in that rush, including three 3-pointers in a 1:28 span by Smart.

By halftime, the Celtics were ahead by 15 points, and Crowder and Smart had 14 points apiece. Covington led Philadelphia with 17, shooting 5-for-6 from 3-point range.