Tony Wroten scored 16 and Evan Turner and Spencer Hawes each had 15 for Philadelphia, which lost its fifth straight game, seventh in a row at home and 15th of 18 overall.
The 76ers (15-35) have lost four straight and 14 of their last 17 games. They also have lost six in a row at home for the first time since the 1996-97 season.
Carter-Williams led Philadelphia with 21 points and Elliot Williams had 18 off the bench.
Thaddeus Young scored 29 points, Michael Carter-Williams added 17 and Elliot Williams had 15 for the Sixers, who have dropped 11 of their last 13 home games, including five straight.
Evan Turner sank a layup at the buzzer to give the Philadelphia 76ers a 95-94 win over the Boston Celtics in a matchup of the two worst teams in the Atlantic Division on Wednesday night.
The Sixers have lost 10 of 12.
Kyle Lowry had 18 points, 13 assists and 10 rebounds, and DeMar DeRozan scored 34 points to help the Toronto Raptors beat the Philadelphia 76ers 104-95 on Friday night.
Michael Carter-Williams led Philadelphia, which has lost seven of eight, with 31. Thaddeus Young had 18. Spencer Hawes had 11 points and tied his season high with 14 rebounds.
Back in October, the Sixers made their first 11 shots and raced to leads of 19-0 and 26-4, putting the champs on their heels a night after they received their rings.
Young hit the final big shot in a fourth quarter loaded with back-and-forth baskets, a contested jumper from the left of the arc off a feed from Michael-Carter Williams.
Thaddeus Young scored 22 points for the Sixers, who have lost three straight after reeling off four consecutive road wins.
The Philadelphia 76ers of the NBA and the New Jersey Devils of the NHL have become the first major U.S.-based professional teams to sign a sponsorship deal with an online gambling company.
Sixers rookie Michael Carter-Williams scored a season-high 33.
Thaddeus Young scored 20 points for the Sixers, who snapped a four-game winning streak. The Sixers had won the final four games of a six-game road trip.
Thaddeus Young had 28 points, Evan Turner had 24 and the Philadelphia 76ers defeated the Sacramento Kings 113-104 on Thursday night for their third straight victory.