The Celtics didn’t lose to the Grizzlies Wednesday night because of poor execution in the final minute when they botched several chances to tie the game or take the lead. They didn’t even lose because they were doubled up on points in the paint.

None of those things helped, of course, but the reason the Celtics lost 90-87 (click here for a full recap) and the reason they have been meandering through the last 10 games has more to do with their offensive inconsistency for 48 minutes than any of those bullet-point lowlights from one game in March.

“We’ve got to get better offensively right now,” Celtics coach Doc Rivers said. “[Assistant coach and defensive guru] Lawrence [Frank] is in there kicking himself and I’m saying, ‘Lawrence, are you kidding me?’ I’ll take 90 points a night. 90 points a night is fine. We’ve got to score more points.”

Over the last 10 games, the Celtics have underperformed offensively seven times based on their average efficiency of 104.5 points per 100 possessions and that poor offensive output has contributed to four of their five losses. That 104.5 number is about league average, so it’s not as if the Celtics had been playing to Phoenix-like levels previously. Lately, they’ve been more like the Bobcats.

For all the questions about their interior defense – and they were entirely legitimate against Memphis – the Celtics primary focus is fixing what’s wrong with the offense and it’s a long list of concerns.

Among them: Poor starts, slow developing sets in the halfcourt, not enough multiple stops on defense that lead to transition baskets and forgetting to get Paul Pierce and Ray Allen involved for long stretches. (You could definitely add Rajon Rondo’s passive-aggressive slump to the mix, but he seems to be pulling himself out of that particular funk, 2-for-12 shooting notwithstanding). This is less about results and more about process and right now the Celtics offensive process is damaged.

They scored just 15 points in the first quarter while shooting 33 percent and turning it over six times and they followed that up by with a 17-point performance in the fourth while shooting 32 percent. Those are the starter’s minutes so it’s not as if this is something that can be blamed on the new players.

Against the Hornets, Allen was 0-for-3 in the first half before getting hot and finishing with 20 points. Against the Grizzlies it was Pierce who was the forgotten man, getting only three shots in the first half but finishing with 22 points on 6-for-7 shooting in the second half.

“As a whole, we’ve got to get back to understanding that Paul is pretty good and he’s got to get more touches,” Rivers said. “That’s on me. I’ve got to get Paul involved.”

As for the players they seem slightly baffled as to why they have been plagued by this bout of inconsistency. Pierce said he’s not making his lack of touches an issue. Rondo suggested they pare down the number of play calls. Kevin Garnett said the slow starts was a topic of conversation in the back room but had no answers on how to fix it.

The defense overall is fine. The lack of size (read: the lack of an O’Neal) hurts, but they remain convinced one or both will be back before the end of the season. The process of integrating new players into the lineup continues with a steep learning curve to be sure, but it continues as evidenced by a tighter rotation and Jeff Green growing into his role as an energizer off the bench.

The issue for the Celtics right now is the offense and they have a dozen games to get it right.

Here are three more points from a turnover-filled night that only Tony Allen could love:

UNCLUTTERING KRSTIC

It was only a week ago when everyone was praising Nenad Krstic for fitting so seamlessly into the flow of the Celtics offense. That’s important to remember because he’s been struggling recently and those struggles tend to get magnified. There was no avoiding the topic after he scored six points and racked up five fouls and four turnovers in 21 forgettable minutes.

“Right now it’s probably between the ears,” Rivers said. “He had three, four, five layups where he’s pump faking and he’s seeing ghosts and that happens. You’re new and you’re learning all this stuff and he’s forgetting that he has to play basketball right now. We have to figure out a better way of unclouding stuff right now and he’s got a lot of clutter going on.”

For his part Krstic said that he simply had a bad night.

“I didn’t have a good game,” he said. “I thought maybe there were a couple of times I got fouled and they didn’t get call it. At the other end I got cheap fouls. Just frustrating and I think it affects you a little bit. I just had a bad game. That’s it.”

But there is an adjustment process happening and after a year and a half of being asked to being nothing more than a pick-and-pop player with the Thunder, Krstic is trying to recapture his post game.

“In Oklahoma City I was a different kind of player,” he said. “Now they want me to play close to the basket. I’ve had some good games. I’ve had some bad games. I’m still adjusting to this system and adjusting to what coach wants of me.”

Krstic has proven he can be the kind of offensive player the Celtics want. Now he just has to get back to that because without either of the O’Neals to provide a buffer for him, he and Glen Davis are it at center.

ABOUT THAT LATE-GAME EXECUTION

It was, in Rivers’ word, “awful.”

The Celtics ran two plays out of timeouts and didn’t get anything close to what they wanted. On the first possession, Davis hoisted a 3 with 7 seconds left on the clock. On the second, Pierce had to attempt a contested 3-footer. Earlier, in transition with a chance to take the lead, Rondo attempted a runner in traffic that clanged off the back rim.

“I got what I wanted,” Rondo said. “I just missed.”

“I probably should have called a timeout on the fast break,” Rivers said. “I honestly thought Rondo was going to hand it off to Paul in transition. Once I saw that I thought, I’ll take that all day. It’s easy to second-guess it now, but I thought we had numbers and I thought we were going to get it to our best offensive player in transition. I’ll take those odds all day.”

“And no,” Rivers added, “Baby was not supposed to take the 3.” 

Rivers defended Rondo’s shot, but again, he wanted the ball to get to Pierce. “I don’t mind when Rondo shoots, ever, but I just think your best offensive player should always touch it on the last possession,” Rivers said. “Listen, he didn’t have a bad shot.”

The problem on the out of bounds plays for the Celtics was that Memphis has two lockdown perimeter stoppers in Tony Allen and Shane Battier and neither let Ray Allen or Pierce get free.

The Celtics run better stuff out of timeouts in late-game situations than just about everybody in the league. On a night when it could have bailed them out, their stuff didn’t work. It happens.

FORESHADOWING THEIR OWN DEMISE

Before the game, Rivers told his team that Memphis leads the team in points in the paint. The Grizzlies scored 52 in the painted area. He also told them that Memphis lives on forcing turnovers and the Celtics committed 20 of them.

“You couldn’t pick a better team for us to play right now because they challenge all the things that we have to get better at,” Rivers said before the game. “It will be a good test for us.” 

Adding insult to injury, it was Leon Powe who did a good chunk of the damage inside, pounding out 13 points in 17 minutes as only Powe can. 

“They clearly played through us tonight,” Rivers said. “Leon Powe was the baddest man on the planet tonight. It’s not like they tricked us with Leon’s sets. They gave him the ball and said just go drive through somebody and score and that’s basically what he did.”

So the Celtics failed those tests across the board. And yet, they still could have -- should have even -- won the game. An even average offensive night would have been enough, and that’s where their attention is focused at this point in the season.