ATLANTA -- There's a sign affixed to a wall near the exit of the Boston Celtics' locker room at TD Garden that has "WE WILL" printed in block letters at the top, then details the five key areas that serve as the backbone of how Brad Stevens wants his team to play.
In the leadoff spot, it says, "Sprint to set OUR defense."
The basic premise is simple: It's more difficult for opponents to score against a set half-court defense than in transition. The numbers illuminate this point. Boston, which tied for the fourth-best defensive rating in the league during the 2015-16 season, allowed 0.882 points per possession while in a set half-court defense and 1.077 points per possession in transition, according to Synergy Sports data.
Part of the reason the Celtics were so good this season is that, despite being one of the most inconsistent jump-shooting teams in the league, they did a decent job of taking care of the ball and made sure to get back after missed shots, forcing teams to play against a set defense. Transition plays accounted for only 12.6 percent of Celtics opponents' total plays this season, the sixth-lowest percentage in a league where the average was closer to 13.7 percent.
During Tuesday's Game 5 loss that left Boston's season on the brink of extinction, the Hawks generated 19 points off 17 transition plays (1.118 points per play). Transition accounted for 14.8 percent of the Hawks' total offensive plays, not an absurdly large percentage but enough of an uptick to help explain how they went from ice cold to unable to miss during an 18-minute stretch in the middle quarters.
Maybe that's why, when asked to assess the way Boston went from limiting Atlanta to 19 points on 6-of-34 shooting (17.6 percent) over the first 18 minutes of Game 5 to allowing 70 points on 27-of-37 shooting (73 percent) over the next 18 minutes, Jae Crowder said, "They got out in transition and hurt us."
Boston's Game 5 troubles were not confined to transition defense. When the Hawks elected to trap All-Star point guard Isaiah Thomas, they challenged his teammates to make open jump shots and -- as has often been the case when Boston struggles in this series -- the Celtics did not take advantage.
Discouraged by their offensive woes, the Celtics were slow at times to get back on defense. Atlanta enjoyed a tiny bit of momentum and rode it into a stretch in which the Hawks made 11 straight shots late in the second quarter while erasing a double-digit deficit and building what would become a 31-point cushion in the second half.
Take, for instance, one late second-quarter sequence in which Thomas finally got a clean drive into the paint. Paul Millsap stepped up with the goal of taking a charge and Thomas, scoreless to that point, was a bit too cautious with a floater. One quick pass and the Hawks were off and running the other way, with Kyle Korver and Jeff Teague leaking out. Amir Johnson had to follow Korver to the corner to prevent a 3 and, late to scramble back, Crowder fouled Teague to avoid an easy layup.
Later in the quarter, the Celtics let Kent Bazemore catch fire by losing track of him in transition. Sometimes, all it took was losing him for a second. Crowder got caught trying to chase a loose ball under the Boston basket and Bazemore sneaked out. While Boston's other defenders rushed back to protect the rim, Bazemore took a simple pass from Millsap, dribbled once and drained a wide-open transition 3.
When Evan Turner turned the ball over on the ensuing possession, Boston was left scrambling to get back again. This time, the ball moved until it found Bazemore in the corner for another open 3-pointer and a double-digit lead.
"I think transition started a lot of it," Turner said of Boston's troubles. "They got a few stops, and in transition we were scrambling around. They kicked the ball out to some open 3s, and from there, it just kind of opened up a lot."
The good news for Boston: The Celtics don't have to reinvent the way they defend to fix the issues from Tuesday night. As Stevens has implored his team this series, Boston has to stick to its principles and utilize them for a full 48 minutes.
Yes, the Celtics must adjust to the extra attention Atlanta will pay to Thomas and hope that others step up by making open shots.
But Stevens is more likely to remind them about limiting those transition opportunities. Boston played stellar defense for the first 18 minutes in Game 5, then lost its way and could never quite recover.
And just in case Stevens doesn't hammer it home enough before Game 6, the Celtics will get one final reminder when they head to the floor Thursday night and see that sign at the locker-room exit before tip-off.