Joe Mazzulla points finger at himself with Celtics down 3-0

MIAMI -- Sunday morning, before the Celtics put their season on the line in Game 3 of the Eastern Conference finals, Jayson Tatum was asked why Boston has been so good away from home over the past two postseasons.

"We've had no other choice," Tatum said. "It was either win, or the season was over with."

Well, the Celtics didn't win Game 3. And, as a result, they find themselves staring down an 0-3 series deficit -- something 149 teams before them have failed to overcome.

After the Miami Heat obliterated the Celtics on Sunday night, leading by as many as 22 points in the first half and 33 in the game en route to a 128-102 victory, Tatum and the Celtics will have to summon something truly…