Ok, let's back up a bit here. Boston dressed 9 players. Wally, Ratliff, Allen, Olowokandi, Scal and Pierce were all out for this game and most have been out much of the season. Wally, Ratliff, Allen and Pierce were considered starters at the beginning of the season. So, we are missing 4/5 of our original starting lineup plus 2 key reserves.
On the other hand, Cleveland dressed 12 guys. The only player who was injured on the Cavs was Lebron James. And James wasn't really injured. He just had general body soreness. They figured that the Celtics were easy pickings and they could beat us without LeBron. It was an important game for them. They lost ground in the playoff race for home court advantage, so it wasn't a game they were looking to lose.
And the Cavs were loaded with veteran leadership. The Celtics veteran leadership included, um, no one. The team that beat the Cavs consisted of one 4th year player (who played all of 35 minutes his first season and not much more his second season), 3 third year players (one of which missed most of last season), 2 second year players, and 3 rookies. So, tell me again, which team was shorthanded?