Boston -- The chest-thumping swagger the Hawks rode to rousing victories before sellout home crowds in Atlanta didn't clear security for their trip to Boston.

Neither did their shooting touch, defensive pressure nor anything else they needed to win their most important road game, to date, of the season.

Instead, the Hawks were run off the floor at TD Banknorth Garden for a third straight time in the series. They lost Game 5 of the Eastern Conference playoff series 110-85 Wednesday in blowout fashion to a Celtics team that appeared to regain a bit of the composure it lost in back-to-back losses in Atlanta.

The Hawks are still alive in this best-of-seven series, trailing 3-2. But Game 6, set for 8 p.m. Friday at

Philips Arena, will be a win-or-stay-home affair for the Hawks, who can force Game 7 back here Sunday with a win or start packing for summer vacation with a loss.

"This is it now," Hawks captain and All-Star Joe Johnson said after scoring a team-high 21 points on 6-for-11 shooting. "It's win or go home. I'm sure it's going to be crazy, and I'm looking forward to it. But we have to come out and take care of home court."

They'll have to use a strategy far different from the slow dance they used Wednesday. The Hawks managed just four fast-break points to the Celtics' 10, a far cry from the up-tempo highlight shows that were Games 3 and 4 at Philips Arena.

"The bottom line is we're not going to beat the Boston Celtics playing half-court basketball," said Hawks forward Josh Smith, who finished with 18 points, five rebounds, three assists and one block. "We're young and we're athletic and we have to use that to our advantage.

"Their advantage on the defensive end is for us to walk the ball across the half-court line and run half-court sets. And we're just not going to beat this team doing that. We have to push the ball and exploit transition points and then pull the ball back out if there's nothing there and run offense.

"We never did that and we got out-toughed on the offensive boards early on, by guys like Leon Powe and [Glen] Big Baby [Davis] early on, and those were key rebounds we needed when we got stops."

There was no chance for late-game heroics from Johnson or Smith, who combined to score all 32 of the Hawks' points in their fourth-quarter comeback win Monday in Game 4.

The Celtics' subs were on the floor by then Wednesday, each of them spending time rubbing the Hawks' faces in the sea of green provided by the sellout crowd of 18,624.

"Every single player gave us a lift with their energy defensively and just pushing the ball up offensively," said Celtics coach Doc Rivers, whose team had a 49-38 rebounding edge and shot 53.6 percent from the floor.

"That's one of the things we kept talking about, that we can run, too. We can't run as fast as them, but we can throw the ball ahead with the pass and run that way. And I thought we did that."

They did it often enough to keep the Hawks on the ropes early, leading by 15 points at halftime, and they did it just enough in the second half to keep the Hawks at arm's length.

When the Hawks cut the Celtics' lead to 60-54 on an Al Horford jumper with 6:22

to play in the third quarter, the Celtics responded with a quarter-ending 21-10 run, with Kevin Garnett, Ray Allen and Paul Pierce leading the way.

Garnett got things started with a turnaround jumper for a 62-54 lead, Allen followed with a 3-pointer and Pierce with a driving layup with 5:24 to play for the finishing touch and a commanding 67-54 lead.

Pierce, dogged by a $25,000 fine for a "menacing gesture" late in Game 3 in Atlanta, flourished in the friendly confines of home, finishing with 22 points, seven rebounds and six assists.

Garnett added 20 points, seven assists and five rebounds. Allen chipped in with 14 points, Rajon Rondo with 12 points and seven assists.

But the real boost came from Powe (10 points and seven rebounds) and Cassell (13 points), no-shows in Atlanta.

"We weren't rebounding the ball well early in the game and they kept balls alive, and it just didn't allow us to get out and run," said Horford, who finished with 14 points and 10 rebounds. "Now we have to go back home and refocus on what we do best and win Friday, because it's a must get for us or else."