Celtics deliver Joe Mazzulla win in coaching debut after turmoil

BOSTON -- After Celtics interim head coach Joe Mazzulla entered the locker room for the first time as a winning coach following Boston's season-opening 126-117 victory over the Philadelphia 76ers on Tuesday night, he gave his players a few moments of praise and encouragement for a comprehensive performance against one of the franchise's oldest and most bitter rivals.

Then, he paused.

"I don't think he knew it was coming," Jaylen Brown would later say with a smile.

The "it" Brown was referring to was the water bottle shower he and the rest of his teammates gave their coach to celebrate his first victory -- which was immediately followed by Celtics owner Wyc Grousbeck presenting Mazzulla with…