Rondo contributed 13 points, 17 assists and 12 rebounds for the Celtics, who erased a 10-point fourth-quarter deficit with a late 12-3 run and pulled out a victory in Game 1 of the best-of-seven series.
Kevin Garnett pumped in a game-high 29 points and hauled down 11 rebounds as the fourth-seeded Boston stayed hot following its 4-games-to-2 defeat of Atlanta in the previous round.
The eighth-seeded Sixers got 19 points from Andre Iguodala.
The two teams will again in Boston Monday for Game 2.
Swim Week Miami Beach 2014 [PHOTOS]