Boston won its fifth straight home game with Pierce hitting 13-of-16 from the field and grabbing eight rebounds.
The Celtics went on a late 12-4 run after Cleveland had battled within 82-80 with 9 minutes to play.
Pierce also produced three steals and five assists while Rajon Rondo added 20 points and eight assists for the Celtics. Jason Terry scored 15 points and Kevin Garnett had 12 for Boston, which hit 59 percent of its attempts from the field.
The Cavaliers, losers of five in a row, were led by Kyrie Irving with 22 points.