He was out coached, more likely than not. Carlisle made some good adjustments with Stevenson and Barea, worked the zone, kept his guys playing Mavericks basketball, and it all followed the plan.
I think Carlisle had more adjustments he could make, though. Spoelstra didn't have a very good bench to work with. He couldn't control his guys tuning him out (Guys? or is it just Guy?).
15 point lead in the 4th, yeah, he could have probably done a better job coaching wise, but the players make the plays, and his star player - Lebron James - decided he was taking his talents to outer space.