Paul Pierce scored a playoff-high 22 points, and Ray Allen turned back the final Hawks' charge with three 3-pointers in a three-minute span of the third quarter on Wednesday night to help Boston beat Atlanta 110-85 and take a 3-2 lead in the best-of-7 series.
The first five games have all gone to the home team, with Game 6 in Atlanta on Friday night.
"We still haven't won a road game, guys," Celtics coach Doc Rivers said. "We have to do it again. We have to do it on the road now. We have to go in there and play like tonight."
Kevin Garnett scored 20 and Allen had 19 to put the Celtics within a victory of advancing to the second round. Boston got a huge lift from its bench in the second quarter, when Sam Cassell scored nine points and Leon Powe had seven with five rebounds while holding Al Horford to a pair of baskets.
"This is my time of the year," said Cassell, who was signed in March as a veteran backup for second-year point guard Rajon Rondo. "I love playoff basketball. I understand what it means. I understand what it takes to be successful during this time of year."
Joe Johnson, who erupted for 35 points in Game 4 -- 20 of them in the fourth quarter -- scored 21, and Horford had 14 points and 10 rebounds for Atlanta. Mike Bibby continued to struggle in Boston, scoring six while recording one assist for the third consecutive road game.
A seventh game, if necessary, would be played in Boston on Sunday, an advantage the Celtics earned with their NBA-best 66-16 record in the regular season. Boston would like to avoid that and get a break from a physical series that saw another flagrant foul -- when Horford took down Garnett late in the first half -- and another double-technical -- when Garnett and Johnson were jawing in the third.
Josh Smith and Hawks coach Mike Woodson also picked up technicals in the aftermath's of Allen's takedown on Horford with three minutes left.
"I won't say we lost our composure," Johnson said. "It's tough when it feels like things aren't going your way. Temper tantrums tend to fly, and that's part of it."
The top overall seed wasn't expected to have this much trouble in the first round with an Atlanta team that went 37-45 to grab the final playoff berth in the Eastern Conference. But the Hawks answered two losses in Boston with a pair of victories at home, tying the series at 2 on Monday night.
Game 4 featured pushing and shoving that wasn't settled until the league announced on Tuesday that there would be no more fines or suspensions. Pierce had already been fined $25,000 by the NBA for a "menacing gesture" -- allegedly gang-related -- during Game 3.
Did it affect Pierce, who scored 18 on 5-for-14 shooting hours after learning of the fine?
"It can't help," Rivers said.
Before Game 5, Pierce issued a statement denying it was a gang sign. Then he went out and put his hands to a more useful purpose.
After picking up his fourth foul early in the fourth quarter, Pierce held out a dismissive arm toward Rivers as if to say: "Relax."
"I won't foul out," he mouthed.
But Rivers took him out, anyway.
And they didn't need him.
"Pierce got it started for them early," Smith said. "Lately he hasn't been getting himself involved in the offense early on, and that's probably been the cause of him not doing well."
The Celtics took a 58-43 halftime lead, holding Atlanta without a field goal for more than seven minutes before Horford's putback dunk with 1:05 left in the second quarter. Pierce drove for a layup to start the second half, then Atlanta scored the next 11 points to pull within 60-54.
But Garnett made a turnaround hook shot, then he passed off to Allen to set up a 3-pointer. Pierce drove for another basket and, after Horford's dunk slowed things down temporarily, Kendrick Perkins answered with a follow dunk that made it 69-56.
After a timeout, Garnett blocked Josh Childress and then Allen hit a 3. Allen threw the ball away and helped the Hawks cut the deficit to 12 points, but then he hit another 3-pointer to give Boston a 75-60 lead.
- A half-dozen members of the New England Patriots were in the crowd, as were Red Sox owners John Henry and Tom Werner. The crowd broke into a few bars of Sweet Caroline after the scoreboard showed the Red Sox scoring the game-winning run in the bottom of the ninth.
- Perkins, who was hit in the nose in Game 3, came out wearing a plastic mask over his eyes and nose. But he abandoned it in late in the first half, Cassell stood in the corner, out of bounds, with one foot on each out of bounds line -- making a big show of staying off the court.