"We could have easily been beaten tonight," Allen said. "We took their hit and we counterpunched."

Kevin Garnett, who had 16 points, also applauded the Celtics' passion.

"I don't know why we look like we're running in mud these days," Garnett said. "But our fight's there, man."

The Celtics, who led 73-58 at the end of the run, had to survive the Hawks' late surge.

Joe Johnson, who had 25 points, had three late 3-pointers as the Hawks rallied. Johnson's 3 with 11.8 seconds remaining cut the lead to 77-76.

Allen, who had 19 points, made two free throws with 10.9 seconds remaining.

Jeff Teague launched an air ball on Atlanta's final possession.

"I overshot it," Teague said, adding he was closer to the basket than he thought on the 3-pointer that could have tied the game.

"We got lucky," said Celtics coach Doc Rivers, who said his team escaped with the win despite "a plethora of mistakes to end the game."

Allen helped the Celtics gain momentum for the final period by sinking a buzzer-beating 3-pointer to end the third period. He scored on a pass from Rajon Rondo, who had 10 points and 13 assists.

Paul Pierce had 13 points for Boston, which took charge with a 17-2 run, including 13 unanswered points, after a 56-56 tie in the final period.

Zaza Pachulia had 16 points and 13 rebounds for Atlanta, which now leads Boston by 1½ games in the race for the sixth spot in the Eastern Conference.

"I told my guys I take my hat off to them, because they very easily could've folded the tent when we were down (15)," Hawks coach Larry Drew said. "We cut it to one. It really comes down to making plays at the end. We had opportunities ... but we just didn't make the plays at the end that we should have."

The Celtics managed only 31 points in the first half and shot only 35 percent from the field through three quarters to trail the Hawks 51-50.

Each team struggled with poor shooting in the first half. The Hawks matched a season low with 15 first-quarter points and set a low for points in a first half, but led the Celtics 33-31.

Fouls became a growing problem for Boston in the third period. Pierce and Brandon Bass drew their fourth fouls with a span of 2 minutes midway through the period.

Bass drew a flagrant-1 technical foul for knocking Pachulia to the floor with 7 minutes remaining in the third. Less than a minute later, Pachulia again was knocked to the floor again by an elbow thrown by Greg Stiemsma under the basket. No foul was called, but Pachulia was bleeding badly from a cut on the top of his head, and he had to be taken to the locker room.

Stiemsma remained in after he was called for his fourth foul with 3 minutes remaining in the period.

Pachulia, who needed stitches, returned for the start of the fourth period.

The Celtics announced before the game that forward-center Jermaine O'Neal will have surgery on his left wrist and miss the remainder of the season, adding more urgency to the team's search for inside help.

"I'm trying to get our team to understand we don't have a margin for error," Rivers said.

Hawks guard Jannero Pargo had an appendectomy Sunday night in Cleveland and is expected to miss two to four weeks.

The Hawks also were without forwards Marvin Williams (hip) and Vladimir Radmanovic (back) and guard Willie Green (hamstring).

Game notes
Hawks C Jason Collins, who missed 21 games with a sprained left elbow before returning to play three minutes against Cleveland, had a more prominent role. ... There was a moment of silence before the game for former longtime Atlanta Journal-Constitution columnist Furman Bisher, who was 93 when he died Sunday of a massive heart attack.