PHILADELPHIA — The Boston Celtics hung on against a feisty Philadelphia team, thanks to their Big Three — and a couple of big threes, too.

Eddie House and James Posey delivered decisive 3-pointers to help the usual, strong efforts of Paul Pierce, Kevin Garnett and Ray Allen hold up for a 113-103 win over the 76ers last night.

“You’ve got to have role players to have a good team,” Celtics coach Doc Rivers said.

House and Posey played their roles to near perfection. The duo went 7-for-13 on threes that made the difference late in the game against a Sixers team with something to prove. Posey scored 17 points, House had 15 and Boston’s bench outscored Philadelphia, 46-26.

“We were just making plays for each other and that helped us in the second half to come back, get a lead and get a win,” Posey said.

Pierce had 19 points and 12 assists, Garnett scored 22 points and Allen scored 12.

Andre Miller kept the Sixers alive until the fourth with his first double-double of the season, a 26-point, 12-assist effort that was one of his best games in Philadelphia. Andre Iguodala scored 24 points.

The Sixers gave an inspired effort in their first game with Ed Stefanski as president and general manager. Stefanski left his job as general manager of the Nets to take a similar role in Philadelphia after Billy King was fired on Monday.

“For 40 minutes we were there, but you’ve got to be able to sustain it against a team like that,” coach Maurice Cheeks said.

Posey hit a pair of threes in the final minute of the third that helped the Celtics take a three-point lead. He hit another early in the fourth that tied the game at 86.

The Sixers went ahead one last time, 88-86, on two of Miller’s free throws. They played hard, played smart, even shot 56 percent from the floor, but they couldn’t stop the Celtics down the stretch.

House hit consecutive threes that sparked a 12-2 run that made it 98-90. Posey hit another three later in the fourth that pushed the lead to 103-94 and the Sixers did not have another run left in them.

“Those are big. They’re back breakers,” House said.