The Celtics did not come ready to play against the Nets on Friday night, opening the game in a 12-point hole after just three minutes. Joe Mazzulla normally is not one to overreact but he couldn't help but calling a timeout after the ugly start to try to snap his team out of it. Beyond the sluggish start though, Mazzulla quickly identified a glaring issue. The starting front court of Xavier Tillman and Al Horford was not going to be a sustainable combination against this uptempo Nets squad.