They had to lose eventually.
Despite a furious rally in the second half, the Bulls couldn't dig out of the hole they created after being down by as much as 23 points.
The loss ended Chicago's 14-game home winning streak and was only the second loss in the last 14 games.
The Boston Celetics lost to the Indiana Pacers, which leaves them and the idle Miami Heat two games behind the red-hot Bulls. The San Antonio Spurs also lost Monday night, which means the Bulls also squandered a chance to gain ground in the race for the league's best overall record.
Derrick Rose led the way for the Bulls with 31 points, but the 76ers countered with a balanced attack that included five players in double figures.
It was the Bulls' first home loss since Jan. 18 against Charlotte.