Boston's Brandon Bass scored 27 points to spark the Celtics to a 101-85 win over Philadelphia and move the franchise within one victory of a place in the NBA Eastern Conference Finals.
Bass found his shooting touch in the third quarter, where he scored 18 points to net a playoff career-high and help the Celtics pull away from the 76ers.
The Game Five win gives Boston a 3-2 lead in the best-of-seven second-round series.
Kevin Garnett added 20, while Rajon Rondo tallied 13 points and 14 assists for Boston, who trailed early but outscored the 76ers 54-35 in the final two quarters.
Elton Brand lead Philadelphia with 19 points
Game Six is on Thursday in Philadelphia.