Of the challengers for a top-four spot, Boston has undoubtedly put together the strongest contender resume. It has gone 19-7 since the All-Star break against a brutal stretch of schedule, lifting the Celtics to fifth in the Power Rankings, and appear to have Miami's number in particular after beating the Heat for a second time in a week. I've already pontificated on Boston's suffocating defense so I won't expand on that too much here, except to note that it is still a bit frail. One more injury to any non-wing player and this whole house of cards may crumble. But for now? The Celtics seem completely rejuvenated, and the higher seeds in the East are justifiably terrified of facing them in an early playoff round.