The Celtics’ Kevin Garnett, right, defends against the Hawks’ Joe Johnson.

The Providence Journal / Mary Murphy

BOSTON — The Boston Celtics know the time is at hand to shoot down the Atlanta Hawks. We’ll see if they’re ready to do the job.

For the third straight time on their home floor at the TD Banknorth Garden, the Celtics controlled the youthful Hawks for the majority of the game and won handily, this time by a 110-85 count. Boston is now in control of this first-round playoff series, three games to two, and will try to close the Hawks out tomorrow night in Atlanta.

Transferring these superior home efforts to the Peach State hasn’t been easy for the NBA’s top regular-season team. The dominating defense that kept the Hawks in check (40 percent shooting) last night was shaky in Atlanta’s Game Three and Four wins. The balanced offense and aggressive bench play that overwhelmed the Hawks last night only showed up in fits and stops on the road.

But with a ticket to the Eastern Conference semifinals within their grasp, the Celtics say they’re looking forward to Game Six.

“The level of intensity we play with at home, for some reason, we have to carry it with us on the road,” said emotional leader Kevin Garnett. “We really have to lock in and carry this over to the road. It’s very important to carry this over to the next game.”

The Celtics played better than the Hawks in every phase last night. They shot better, were more aggressive off the backboards (39-28) and locked the Hawks’ key scoring stars up most of the evening. Joe Johnson, a killer in Atlanta’s Game Four comeback win, led the Hawks with 21 points but he never found his scoring groove in the critical fourth quarter.

Boston received offensive help up and down its lineup. Paul Pierce led the way with 22 points on 10 of 17 shooting. Garnett added 20 points and 7 assists and Ray Allen sank five 3-pointers and finished with 19 points.

The Celts also welcomed a big lift from the bench. Leon Powe (10 points, 7 rebounds) was outstanding in the first half, Sam Cassell (6-of-8, 13 points) provided a big scoring spark and James Posey played sticky defense in reserve.

“We were better on both ends,” said Celtics’ coach Doc Rivers. “The offensive execution was as crisp as we’ve had in a month. On defense we did what we should do and we did it well.”

The Hawks trailed by 15 at halftime, cut the deficit to six early in the third but lost control the rest of the way. The Celtics led, 81-64, after three and never saw their lead shrink below 13 points in a raucous fourth quarter. Technical fouls assessed to coach Mike Woodson and forward Josh Smith in the game’s final three minutes ended an ugly night for the visitors.

“I won’t say we lost our composure,” said the Hawks’ Johnson. “It’s tough when it feels like things aren’t going your way. Temper tantrums tend to fly. That’s part of it.”

Johnson said that he doesn’t see his team quitting just yet. “We still got life, man. It isn’t over yet. We have to go home and take care of business and that’s that.”

The Celtics essentially sewed up the game in the opening 24 minutes. Boston’s defense returned to an aggressive, trapping style and the Hawks struggled finding any rhythm. The visitors stumbled with early foul woes that hindered Johnson as the Celts sprinted out to a 58-43 halftime lead.

The Celtics began the game with great energy and when Johnson picked up his second foul and left the game at the 4:26 mark of the opening quarter, the home team closed strong with Pierce finished the quarter with 10 points.

The Celtics did not have a single turnover in the opening quarter and that dazzling statistic nearly continued through the half as the Celts lost the ball just one time on the way to the commanding lead at the break. Powe (7 points, 7 rebounds) was a force in the lane in the first half while Cassell led all scorers in the second quarter with nine points on 4-of-5 shooting.

The Hawks struck early in the third quarter as an 11-0 run capped by Al Horford’s 15-foot corner jumper cut Boston’s lead to 60-54. But the Celts quickly counterpunched with seven straight points and kept rolling with a 12-2 spurt capped by another Allen 3-pointer for a 72-56 lead.

The Hawks shot just 35 percent in the third quarter and an early Boston push in the fourth extended the lead to an insurmountable 89-70 early in the fourth quarter.

Next Game

Tomorrow

at Atlanta

8 p.m.

kmcnamar@projo.com