Joe Mazzulla’s Celtics embrace watching and learning from NBA rivals

BOSTON — Payton Pritchard turned on the West playoffs like he normally would while the Celtics enjoyed several days off last week awaiting their opponent between the second round and the conference finals. Instead of casually watching the game, he found himself analyzing it — a habit the Celtics have carried into this season under Joe Mazzulla’s tenure. Pritchard did this work on his own, eyeing the things Mazzulla wanted Boston to learn from.

“Easy. If a team goes on a run, how bad of a run is it? Can we regroup and make it a 6-0 run, or are we gonna turn it into a 15-0 run. I watched the game last night, the Thunder-Dallas,” Pritchard said. “Dallas ended up winning, but at the end of the…