ATLANTA – The regular season is too long, the nagging injuries pile up and it’s simply hard for a veteran team to get motivated when it knows the real stuff doesn’t begin until April.

But if there was ever a game in which the Celtics would want to make a stand it was last night’s. The Hawks had beaten them in the first three meetings, and you could almost hear them singing, “Who’s afraid of the big, bad Celts?”

The Bostonians wanted this one but still fell, 100-91.

So were the Celtics unwilling or unable?

The Hawks swept the season series, and the Philips Arena public address announcer taunted them as they left the court, saying, “Is it a rivalry now?”

Paul Pierce was brilliant with 35 points, but former Celtic Joe Johnson scored 16 of his 27 points in the last quarter to put the C’s away. Jamal Crawford added 28 off the bench.

“It definitely bugs me,” Pierce said. “You don’t want to lose. When the playoffs start, it’s all 0-0, but they feel like they have the edge.”

The Hawks will continue to have an edge if the C’s don’t do more to get the ball out of the hands of scorers on a roll.

“We’re not doing a good job of that,” Kevin Garnett said. “And we’ve got to.”

Added Pierce: “We let them isolate us, and that’s the way they play. They did it four games vs. us. I think we should have done a better job with our help defense, getting another man to bother him. When those guys get going, they can really go off.”

The normally even-handed Ray Allen was visibly upset after this one.

“It’s just frustrating,” he said. “After you lose it’s best always to reserve your opinion.

“Obviously there are some things we could have done a lot better – better execution on offense, defensively what were we doing? But we’ll watch film, and it’ll give us a fresher perspective.”

The Celtics saw a nine-point first-quarter lead dissolve into a 14-point deficit by the second quarter. Pierce had 14 in the third when the Celts made 19-of-20 free throws to get within a point.

But Johnson began winning one-on-one battles with whomever the Celts threw his way in the fourth. He made 7-of-9 shots in the quarter.

The visitors fought back to within five with 1:30 left, but Johnson drove on Pierce and then hit a 3-pointer to ice it. That kept Doc Rivers from clinching the Eastern Conference coaching job in the All-Star Game.

He’s got to be more concerned about the pack gaining on his team.

“When you’re good, teams are going to go and do their knowledge,” Garnett said. “They’re going to get better and get better schemes. I think teams are not necessarily catching up, but they’ve done their homework. They’ve seen the chinks in the armor. You know, we didn’t win it last year, but teams are coming out and playing us like we’re the champs. That’s respect. Now we’ve just got to figure out a way to make an adjustment or go to another level and just get our consistency back, just playing hard-nosed.”

Rajon Rondo delivered what might be construed as a shot when he was asked about previous teams not facing this adversity and said, “I try not to look back on the past. It’s a different team this year. That’s our problem. A couple of years ago, we didn’t have the same team. We had the same main guys, but it’s still a team effort, from the first guy to the 15th guy.”

Garnett was a little more selective.

“The words that we want to use, you guys can’t write in your column or put on this television,” he said. “But we’re going to get better. We’re too prideful, too competitive as men to go another route.”