How the ultra-competitive Joe Mazzulla is challenging the doubters -- and what it means for the Celtics - ESPN

Boston Celtics players couldn't help but give each other knowing smiles this week when first-year coach Joe Mazzulla had his drop-the-mic moment.

For three years, Mazzulla was one of those assistant coaches who built deep relationships with players. His job in Boston was mostly player development, which meant hours of one-on-one work after practices and before games that created bonds.

It also meant that, away from the gym, he was in the card games and the board games and, perhaps most intensely, the ping pong games. He was involved in a way head coaches and veteran assistants usually aren't with players.

And so the players and staff members who know him well weren't surprised when he fired back at critics.

«What, no one wants to ask about the adjustments we made from Game 1 to Game 2?» Mazzulla snapped as he walked off the podium following the Celtics' 34-point win.

Mazzulla — the youngest coach in the NBA at 34 — was fiery in response to the notion that he'd been outcoached by Philadelphia's future Hall of Fame coach Doc Rivers in Game 1.

«So this is the thing, he's an ultimate competitor and he wants to compete in everything he does,» Celtics forward Grant Williams told ESPN after Boston secured its second straight win in the series on Friday to take a 2-1 lead going into Sunday's Game 4 (3:30 p.m. ET, ESPN).

«He's going to give it back if it's given. Some people will call that immaturity, other people will call that confidence, and I think it's the latter,» Williams said.

Here's another thing: Rivers did outmaneuver Mazzulla in Game 1 when he used James Harden in a throwback role, putting the ball in his hands and creating isolation opportunities as the central part of the game plan, savaging the Celtics' defensive