Ellis also had eight assists and Nowitzki finished with 18 points, including a trey off a Jose Calderon feed with 3:11 left in the game that turned back an Orlando rally.
DeJuan Blair also had 18 points off the bench as Dallas began a three-game homestand with a win.
Arron Afflalo paced the Magic 25 points.
Nikola Vucevic had 16 points and eight rebounds.
Swim Week Miami Beach 2014 [PHOTOS]