Ime Udoka spent one season as Steve Nash’s assistant. And in his first postseason as a head coach, he is schooling him. Udoka, who designed the NBA’s top ranked defense, is now wielding it like a two-by-four. The Celtics are manhandling Durant. They are squeezing Irving. Bruce Brown and Goran Dragic scored 30 points in the first half. In the second half, they scored 11. Offensively, Boston is engineering switches onto Brooklyn’s smaller guards and bulldozing them.