Brandon Bass opened the second half by missing an uncontested putback from two inches away. Kevin Garnett missed a bunny on the next possession. Shortly thereafter, Mickael Pietrus caught the ball with an open court in front of him. He stopped, gathered his surroundings, and threw a pass to the wrong team.

With 3:08 remaining in the third frame, Joe Johnson canned a three-pointer to put the Hawks ahead 65-54. The Celtics looked lost without Rajon Rondo and headed to a second consecutive defeat. Paul Pierce had cooled considerably after hitting his first four field goal attempts and nobody else on Boston’s roster seemed very interested in putting the ball through the rim. On the other end Atlanta found all too many buckets inside the paint, where the Celtics interior defense repeatedly and uncharacteristically parted to allow Jeff Teague free passage.

What followed could be labeled a Celtics run to steal their 87-80 win, but calling it a run implies a freedom of movement, a certain ease these Celtics hardly ever demonstrate. Winning NBA games is not easy. Winning the way Boston does it — without much offense, especially in the absence of Rajon Rondo — requires a sustained level of effort and dedication and doggedness that most people I know simply aren’t capable of achieving, not just in basketball games but anywhere else in life. The Celtics didn’t make a run to win Tuesday’s Game 2 so much as they built a moat around the hoop to impede any Atlanta progress, to slow Atlanta to a crawl, to ensure that any bucket the Hawks got would be both contested and hard-earned.

These Celtics thrive when games become covered in mud and points are more difficult to come by than a left-handed starter who throws 100 MPH with command. They’re at their best when Avery Bradley’s chest is stitched to his opponent’s and Kevin Garnett is making perfect rotations and the entire team gang-rebounds like hell. They like it when games result in bruises and muscle sores and baths filled with ice.

“That’s who we are,” Doc Rivers said in his press conference while discussing grind-it-out affairs.

The Celtics didn’t just win because Paul Pierce erupted for 36 points and 14 rebounds, the type of performance he can frame and put above his mantle and about which we will tell our grandchildren one day many years from now. They won because Ryan Hollins gave them good minutes, Keyon Dooling hit two clutch threes just when Atlanta threatened to turn the contest into a blowout, and Marquis Daniels scrubbed off several inches of dust to provide 15 intelligent minutes. They won because Bradley does not stop for breaths, Garnett isn’t a fan of allowing opponents to score and Doc Rivers decided, “Hell, why don’t we give the small lineup a try?” They won because they kept Atlanta to 14 fourth-quarter points, because they held the Hawks to 34.9 shooting for the game, because Joe Johnson and Jeff Teague couldn’t find any freedom during the final quarter, because the Celtics didn’t allow any of the Hawks to shoot better than 50 percent — and the one Hawk who managed to hit half his shots, Jason Collins, was just 1 for 2.

Without Rondo, the Celtics’ small margin of error only became slimmer. But these Celtics know what they need to do to win, and so when they trailed by 11 points during the third quarter, when everything seemed to be unfolding against them, when an 0-2 series deficit was becoming reality, they did not wait for a bar fight to erupt. Rather, they grabbed the closest beer bottle and started one themselves.