Lowe: Brad Stevens and the Celtics have a special brand of toughness

[police brutality]

Boston is talented, but this wasn't supposed to happen. Here's how Danny Ainge, Brad Stevens and the players have addressed the challenge.

More... (http://www.espn.com/nba/story/_/id/23465885/zach-lowe-boston-celtics-toughness-nba-playoffs)