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The modern NBA is about as friendly to comebacks as any sport has ever been. The proliferation of 3-point shooting means that scoring vast quantities of points very quickly, or, simultaneously, missing a ton of difficult shots over the course of several quarters, means that there are very few truly safe leads in basketball. One barrier that hadn't been crossed this season, though, was the 30-point comeback. 

When Al Horford drilled a 3-pointer with 4:23 remaining in the second quarter of Monday's game between the Boston Celtics and Atlanta Hawks, he pushed his team's lead up to that 30-point threshold. That effectively meant that the game was over... right? Well, you read the headline. Obviously, it wasn't.

From the moment Horford hit that 3-pointer until the end of the first half, Atlanta went on an 18-6 run. It proceeded to continue chipping away at that lead, winning the third quarter 34-22. And then, finally, a Wes Matthews 3-pointer with 9:58 remaining in the fourth quarter gave the Hawks the lead back at 97-96. 

The two sides went back and fourth for the remainder of the fourth quarter, but DeJounte Murray took the lead back for good with one minute remaining, and De'Andre Hunter sealed it with a 3-pointer that gave Atlanta a four-point lead with 10 seconds to play. After the game, Celtics coach Joe Mazzulla tried to look for the positives.

"It's a good lesson," Mazzula said. "When you let a team hang around, they made those margin plays, points off turnovers, 3-pointers, offensive rebounds. Credit to them for battling back."

It's a lesson that the Celtics seem to learn pretty frequently. After all, it was less than three weeks ago on March 5 that Boston blew a 22-point lead to the Cleveland Cavaliers in a humiliating nationally televised defeat. Boston has lost only 15 games all season, but has blown double-digit leads in more than half of those games (eight). Last season, the Celtics blew a 28-point lead at home to lose against the Brooklyn Nets.

Historically speaking, topping that embarrassment seemed nearly impossible. Entering Monday, only nine teams in NBA history had ever blown a 30-point. Now, the Celtics have made it an even 10. Fortunately, it wasn't quite the biggest blown lead in league history. That dubious honor belongs to the 1996-97 Denver Nuggets, who allowed the Utah Jazz to turn a 36-point deficit into a four-point victory.

Most teams, even the best ones, blow a handful of big leads every year. That's just a function of the league's current shot profile and its 82-game schedule. Boston loses so rarely that any single loss is going to be magnified. Every other team in the league has lost at least six more games than the Celtics. To some extent, that magnifies their rare failings. That they were missing Jrue Holiday and Derrick White against Atlanta should offer some relief. The Celtics weren't at full strength.

But the Celtics have developed a troubling habit of falling asleep at the wheel. You can get away with that in regular-season March games. They still have a 10.5-game lead for the No. 1 seed in the Eastern Conference. This wasn't a game they needed to win. But this kind of inconsistency can be the difference between survival and elimination in the postseason. Even if the Celtics don't lose often, it's not a great sign that so many of their losses seem to come in the same fashion.