Howard, who criticized his coach for his lack of scoring chances in Game Five, combined with team mate Rashard Lewis' 20 points to tie the best-of-seven series at 3-3.
"I got myself open and ran the floor. That's what I have to do, I can't worry about touches," Howard told reporters. "I got offensive boards and was active, and that's what I have to do if we're going to win.
"We're going to Boston to get Game Seven."
Rajon Rondo recorded 19 points, 16 rebounds, and six assists for Boston, who led for most of the game before the Magic outscored the NBA champions 22-13 in the fourth quarter.
Paul Pierce, who had 17, scored six straight points to give the Celtics a 73-72 edge with 4:50 left but Hedo Turkoglu drilled a three-pointer with 1:23 remaining as part of an 8-0 run to close out the game for Orlando.
