Philadelphia trailed 72-70 midway through the fourth, before going on a 15-4 run that put the game away with 1:50 left. Andre Iguodala, who entered the game averaging 14.8 points, was held to seven - although four came in the fourth quarter.
Wesley Matthews scored 26 points and LaMarcus Aldridge added 20 for the Blazers, who struggled again in the fourth quarter.
They managed only 13 fourth-quarter points in a 97-78 home loss to New Orleans on Friday, then collected just 18 points in the final period in a loss to New Jersey.
The Blazers were even worse on Tuesday, scoring just 11 points in the final period. Portland was 4-for-20 from the field in the period. It was the second game of a four-game East Coast stretch for the Blazers, who have dropped four straight.
The teams played evenly through the first two quarters, with Philadelphia holding a 47-46 lead at halftime. The Blazers built an eight-point lead thanks to a 10-1 run to start the third quarter, their biggest advantage of the game.
Many of those baskets came on layups, as Portland consistency fed the ball inside. The Sixers adjusted and forced the Trail Blazers into lower percentage shots.
Notes: The Sixers assigned Craig Brackins to their NBA Development League affiliate, the Springfield Armor. The rookie had appeared in one game this season, scoring six points in 10 minutes at Toronto on Nov. 24. ... Swingman Jason Kapono returned after missing four games due to personal reasons. ... Portland centers Joel Przybilla missed his second straight game with the flu.