There’s a hackish lead in here somewhere. Something about a tale of two halves. But cliché as it may be, there’s something to that.

The Celtics came out and played the first half against the Indiana Pacers like they were getting ready to visit Disney World, which coincidentally, some of them probably going to do in the next few days when they head to Orlando.

“All I told them at halftime was our defense was awful,” Doc Rivers said. “Our energy was awful. Our offense was fine. We were missing good shots for the most part.”

The second half from an energy standpoint and from a defensive standpoint was much more to the coach’s liking and the Celtics were able to escape with a 103-94 victory before heading out on the road to play the Magic on Christmas Day. The first West Coast swing follows.

They did it without Kevin Garnett (more on that in a bit) and the good news is that it wasn’t KG’s knee that made him a DNP. Rivers said it was thigh bruise, which Garnett apparently suffered against Memphis on Dec. 14 and which has been bothering him since. Garnett didn’t tell anyone about it until earlier in the week and he actually sat out part of practice, which prompted Paul Pierce to tell him, “You’re growing up.”

Rivers said he made the call to shut KG down after watching him in the shootaround and that Garnett protested but ultimately understood.

The prevailing thought is that Garnett will be good to go against the Magic and on the rest of the trip. That’s the good news. The bad news is that KG’s absence looked eerily familiar, and that segues nicely into the first of our three things:

AS KG’S HEALTH GOES, SO GO THE CELTICS' CHANCES

There is always a “knock on wood” quality to talking about the Celtics this season. If Garnett is healthy, not to mention the other 30-somethings on the roster, then the Celtics are as a good a bet to grab a piece of the Larry O’Brien Trophy as any other. Knock on wood.

“The fate of how far we go lies in how healthy Kevin is and our team,” Pierce said, and that’s nothing but the truth from The Truth.

The presence of Rasheed Wallace helps mitigate some of this. That sure wasn’t Mikki Moore running around racking up fouls in Garnett’s absence, but the Celtics play had a distinctly familiar feel, and it wasn’t good.

“It’s pretty much the same as last year when we didn’t have him to close the season out,” Rajon Rondo said.

For starters, there was the defense or the lack thereof in the first 24 minutes. There also was a lack of flow offensively and a definite lack of communication.

“You’re talking about a guy who we play our offense through, our leader on defense,” Pierce said. “We said at halftime that we weren’t talking on defense and usually Kevin leads us in that category. I guess it took us a half to realize Kevin wasn’t going to be out there.”

Rivers made the decision after the team’s shootaround but didn’t tell anyone about it — players or press. If it was a test, you’d have to give them a C+, graded on a curve.

“It’s just like last year,” Rivers said. “It’s no different in some ways. You know when Kevin went out last year we had the ability to score. We just couldn’t stop people from scoring. And I actually turned to [assistant coach Tom Thibodeau] in the first half and said, ‘Here we go.’ ”

The Celtics did regroup and Wallace was a huge part of that effort. The difference between him and Moore is deep and vast. But KG’s health is the reason why it was always pointless to speculate about winning 70 games or potential playoff matchups.

As the estimable Bubbles once said on “The Wire,” it’s a thin line between heaven and here. That’s where the Celtics stand with and without Garnett.

THIS WASN’T PAUL PIERCE’S FIRST TIME AT THE RODEO

Someone asked Pierce after he started the game missing his first 10 shots and finishing with 21 points if this game was a little strange for him. A slight smile appeared on his face before he brought up a little piece of Celtics lore with which he was intimately involved.

It was way back in 2002 when the Garden was better known as the Jungle and Antoine Walker was riding shotgun with Pierce. In the epic playoff comeback in Game 3 against the Nets, Pierce shook off a similarly dreadful first half and finished with 28 points, capping off the whole thing with his iconic jump up on to the scorer’s table. 

“I’ve been in this league long enough to shrug off shooting slumps,” Pierce said. “The shots I was getting were good shots. I wasn’t going to force it, but I was getting great shots, man. I thought something was wrong with the rim, not with me.”

Down the stretch, Pierce relished in the matchup he had with Dahntay Jones, who had tormented the Celtics back in November. This was his element and he relished it.

Unprompted, Rivers also brought up the Nets game and proceeded to distill the difference between the Paul Pierces of the world and everyone else.

“It’s funny, I use the players a lot when I talk to my kids about sports, and I always use Paul,” Rivers said. “I wasn’t here, but he had that game against New Jersey. Shooters always believe they can shoot. That’s the difference between the average player and the great player. The average player stops shooting and turns it into a bad game. The great player is thinking the next one is going to go in. It’s an unshakeable confidence.”

There was no wild celebration after this one. After all, it was just another game in December and it’s not the first time for Pierce.

SHELDEN WILLIAMS HAS GONE MISSING

On a night when the Celtics were without their best big man, Shelden Williams was conspicuously absent from the C's victory. Brian Scalabrine soaked up the available backup minutes, which Rivers said had a lot to do with the Pacers personnel, particularly Troy Murphy, Indy's long-range-shooting big man.

Rivers almost tabbed Scalabrine to start the second half to change up the look but ultimately decided to stick with Wallace. In fact, Rivers played only seven players in the second half (again, shades of last season’s playoffs).

After a strong start, Williams has seen his playing time dwindle in non-blowout games. That trend certainly will continue when Glen Davis comes back from his thumb injury. Davis is expected to accompany the Celtics on their road trip but isn’t expected to see action until the team returns home and plays Toronto on Jan. 2 at the earliest.

Williams has shown the ability to rebound, and while his offensive game is as limited as advertised, he has been a very useful part of the rotation. Depth is a good thing, but Williams’ time in the spotlight may be coming to an end for now.