The Celtics have won three straight and appear to have righted the ship. It all starts with defense and slowing down the game, and they’ve been trying to find a rhythm for the last three weeks. Slowing the pace, combined with being healthy, is working just in time before the start of the playoffs. Boston has stayed Under the total in eight of its last nine games while Portland has done so in four of five, including each of its last three. The Under is the play.