Ugly history does not die easy. Neither apparently do NBA franchises with 17 league championships and a blur of Hall of Famers, even if the current incarnation of the Boston Celtics is viewed more as a cute overachieving bunch going nowhere this postseason.

Exactly where the Hawks are going remains in doubt. After jumping to a 2-0 series lead over a franchise it has never beaten in a playoff series (0-7) since setting up in Atlanta, the Hawks were facing a wounded Boston team that was down a starting guard and a center and felt desperate enough to change two other starters.

But you just had to know it wouldn’t be that easy, right?

Boston led 19-6 before you could say, “Game 5.”

The Hawks fell behind by as many as 20 points in first half and trailed by 19 in the third before scrambling back to daylight and even momentarily take the lead at 78-77. But they seemed to have nothing left after the comeback and wilted on defense. Isaiah Thomas, a 4-for-15 mess in Game 2, poured in 42 points, and the Celtics dumped the Hawks 111-103 at TD Garden.

So the series lead is down to 2-1.

“I knew we were going to compete — I was just worried that we were going to run the first lap of the mile too fast and not have anything at the end of the day,” Boston coach Brad Stevens said.

Turns out the Celtics have more left than most thought. Then again, isn’t this how it often goes with the Hawks? They jumped out to a 2-0 lead over the Brooklyn Nets in the first round last year, only to lose two games on the road before winning the series in six games. They’ve never swept a best-of-seven series and they’re now 1-5 in Game 3s after taking a 2-0 lead.

They can take comfort in knowing they’ve never lost a seven-game series after leading 2-0 (5-0). But the fact they just lost a game to an undermanned team overshadows everything right now.

Well, other than this: Thomas, in addition to torch the defense, delivered a swinging forearm slap to Dennis Schroder’s face in the first quarter. Somehow, the play didn’t draw a foul but it’s expected to be review by the league. Could Thomas, Boston’s best player, be suspended for Game 4?

Schroder told the AJC, "I'm not going to let nobody slap me in my face. I told him (the referee). If you want to play like that, we'll play like that. I was mad."

This game was far more physical than either of the first two. Bodies hit the floor. There were flagrant fouls and reviews for several others. Thomas and Dennis Schroder were called for double technical fouls (which is what referees do when they didn’t see who started it).

Thomas also threw a swinging forearm to Schroder's face as he was running up the court. (Officials didn't see that either, but Twitter did. And anything Twitter sees, the NBA will see.)

It was like real playoff basketball that probably would have impressed even sometimes old and bitter players from the 1980s who can be dismissive of today’s game.

This was a series most projected would go six or seven games, Many had the Celtics winning (ESPN’s panel of 21 writers tipped in Boston’s favor, 11-10.) But the Hawks have been somewhat overlooked nationally because of their significant dip from 60 wins last season, and the Celtics are beat. They lost two regulars in the series opener, starting guard Avery Bradley (hamstring stain, like out for the series) and center Kelly Olynyk (aggravated a shoulder injury).

Also, it’s never a good sign when an NBA coach feels compelled to change 40 percent of his starting lineup for a playoff game, but Stevens was feeling a little desperate, especially after seeing his team smoked 21-3 to open the last game. So Stevens benched starters Marcus Smart and Jared Sullinger and summoned Evan Turner and Jonas Jerebko.

Was there some science behind this decision? Hardly. Stevens was asked before Game 3 if he based that decision on his “sample size” of when Turner, Sullinger, Thomas, Amir Johnson and Jae Crowder have played together, and he almost laughed.

“They’ve played a whole 33 possessions together. They’re a plus-20,” Stevens said, smiling. “So the sample size from an analytical viewpoint is not strong.”

But whatever he did worked — for everybody in green. Boston, which scored seven points in the first quarter of Game 2, opened Friday with 37. They led by 17 points after one quarter (37-20), by as many as 20 in the second. The Hawks were dreadful on defense, missed open shots, couldn’t hit from outside the 3-point arc (2-for-17 in the half).

The Hawks went on a 12-0 run to cut it to seven, caught Boston at 77-all and eventually took a 78-77 lead and a driving layup and free throw by Schroder, their first lead since 4-3. But Boston took it from there. And it appears we have a series.

“They threw a heck of a blow coming out of the first quarter, and some nights you’re just on the wrong side of that,” coach Mike Budenholzer said. “Could we be better? Yes. But I’m not going to be overly critical of how we responded or how we came out.”