The Celtics problems with back-to-backs have been well-documented this season, especially on the road where they were 2-7 on the second night heading into Monday’s game at New Jersey. True to form the Celtics played great in spurts, but looked tired and slow in others and lost, 88-79.

Like many of their losses in similar situations, this was a winnable game, but the Celtics didn’t make the plays. They have now lost the second game of back-to-backs five straight times on the road and with four more back-to-backs left this season and three of them on the road, they will be tested again.

WHAT WENT WRONG

Rajon Rondo continues to struggle: The last time Rondo played a truly great floor game was March 4 when he scored 16 points and had 15 assists in a win over the Suns. Since then he’s had a couple of so-so games mixed in with some complete bombs. Rondo went 0-for-6 in the first half with four turnovers, but things got worse for him and the Celtics when he left the game with a sprained ankle early in the third quarter. Rondo returned but committed a terrible foul on a 3-pointer late in the game and finished 1-for-10 from the floor.

Foul trouble: Less than two minutes after Rondo limped off, Paul Pierce walked off with his fourth foul. He was followed closely by Nenad Krstic, which upset the Celtics’ early second half momentum. The Celtics found themselves down by seven at the end of the third quarter and had to play from behind for the rest of the fourth.

Energy level low: The excuses are tired and so were the Celtics, but if they had played moderately better against New Jersey, Washington and Charlotte — to name three — in the back-to-backs, they would have a comfortable margin to play with down the stretch. It could ultimately cost them the top seed in the East.

WHAT WENT RIGHT

Glen Davis is a difference-maker: There are times when Davis’ impact in the game can be readily seen in the box score, like Monday when he had 16 points and a season-high 14 rebounds. But when Davis is at his best, his game has more to do with charges, loose balls, long rebounds and all the kinds of things that save possessions. His absence was felt dramatically over the last week and a half.

Carlos Arroyo continues to impress: Delonte West is on course to return Wednesday when the Celtics host the Pacers, but West may have some competition for backup point guard duty. Arroyo had another strong game with four points, four rebounds, three assists and just one turnover in 16 minutes. Whatever happens with the position, Arroyo has proven to be more valuable than just an emergency fill-in.

Kevin Garnett is back in a groove: Garnett recently had a six-quarter shooting slump, which was magnified by the fact that the Celtics lost both games during his skid. But Garnett never stays cold for long and after going 9-for-14 against the Nets, that’s at least one small thing that was a positive Monday.

For three-plus seasons, the Atlantic Division has been the Celtics kingdom. All of a sudden, it has become a madhouse. A day after the Knicks acquired Carmelo Anthony, the Nets swooped in and landed Deron Williams from Utah for Devin Harris, rookie Derrick Favors and draft picks. Harris and Favors were two of the key pieces in the Nets pursuit of Anthony, but there’s two significant differences here.

First, unlike the Anthony saga, which dragged on throughout the entire season, the Nets-Jazz trade was consummated quickly and with zero media attention. Second — and most importantly — the Nets made the move with no assurances that Williams would sign an extension before he can opt out of his deal after next season. Indeed, Williams was as unaware as everyone else that this deal would go down.

Williams can’t sign an extension until the summer, which leaves New Jersey a limited window to sell their new point guard on the prospect of headlining the franchise once it relocates to Brooklyn.

The deal has layers of ramifications and intrigue. Obviously the Nets have to be giddy about stealing some of the limelight from their brethren across the Hudson river, but beyond that the Jazz are now armed with high-value draft picks and young big men including Favors, Paul Millsap and former Celtic Al Jefferson. This also closes an unfortunate chapter in Utah’s history that began when longtime coach Jerry Sloan left the team after a reported blowup with Williams about the direction of the team.

For now, though, Williams is New Jersey’s most significant addition since it pried Jason Kidd loose from Phoenix. If he stays, the prospect of Williams matching up with Rajon Rondo four times a season is enticing. As an added bonus, if the Knicks actually are able to snag Chris Paul in free agency after next season, the Atlantic Division will become point guard central.

The issue for the Celtics is obvious. They will be a much different team after next season (assuming there is a next season). All of their key players besides Rondo and Paul Pierce will either be off the books or have new deals in place. With the Knicks, Nets and even the young 76ers gathering steam, competition will be fierce and the Celtics will be facing an overhaul. That’s a discussion for another day — and another collective bargaining agreement.

We haven’t yet reached the zero-hour of this season’s trade deadline, but it’s hard to imagine anyone else making a bolder, and more far-reaching move than the Nets did when they shook up the NBA and acquired Williams.

The Celtics have a well-worn reputation for playing sub-par basketball on weekend afternoon. With a younger team one might worry about nocturnal activities, but the veteran Celtics are simply creatures of habit. They just don’t like having their routines messed with.

They turned that bit of conventional wisdom on its head with a thorough dismantling of the Nets in New Jersey, 100-75 as five players scored in double figures and the Celtics held New Jersey to just 38 percent shooting.

The Celtics have now won seven straight games and have the top record in the Eastern Conference at 16-4. These wins will look a lot more important in March when that race really starts to take shape.

THREE THINGS THAT WENT RIGHT

Bench production: At the beginning of the second quarter, Doc Rivers trotted out this unfamiliar lineup: Avery Bradley, Von Wafer, Marquis Daniels, Glen Davis and Shaquille O’Neal. This was Rivers’ original vision of a second unit with Shaq anchoring the paint.

As it turned out it was Davis who took control from the middle, working rookie Derrick Favors on the block. Davis finished the first half with 12 points and five rebounds, Daniels added eight points and the Celtics outscored New Jersey, 30-12 in the second quarter to take command of the game.

Davis finished with 16 points and nine rebounds in 30 minutes and was +27 in raw plus/minus.

Strong start for Nate: With Rajon Rondo out to rest his sore hamstring (see below), Nate Robinson got the start and got the Celtics off to a fast start with eight points in the first five minutes. Rather than try to be Rondo, Robinson did what he did best — which also included launching 3′s early in the shot clock and on the fast break.

That’s all part of the package for Robinson and it’s worth noting that Rivers encourages him to play that way. But Robinson didn’t just look for his shot. He also dished out six assists to go with six rebounds in what might have been his best game of the season.

Board work: The Celtics dominated the glass, outrebounding the Nets 49-36. Kevin Garnett led the way with 14 rebounds in just 26 minutes of work. He now has 11 double-digit rebounding games, equal the amount he had all of last season.

TWO THINGS THAT WENT WRONG

Rajon Rondo misses another game: Apparently, the hamstring is still an issue for Rondo. He was a late scratch on Sunday and has now missed four of the Celtics 20 games. The only remedy for a hamstring injury is rest and the Celtics have a few days off before playing Denver Wednesday at TD Garden.

The good news is that they have found ways to win games without Rondo in the lineup (they have now three of those four). The bad news is that it looks like Rondo will be dealing with something for most of the season. There is no question about Rondo’s pain tolerance, but it will be pushed in ways it never has been before.

Injuries (again): Jermaine O’Neal told reporters in New Jersey that he will begin workouts next week and then hopes to practice with the team the following week. If, and it still seems like a big if, they can have O’Neal back by the new year it would be a huge boost for the Celtics.

Their depth is painfully thin right now and one more frontcourt injury could have a disastrous effect on what has been a fantastic start to the season. Shaq missed the second half with a sore right calf. The Celtics didn’t need him Sunday, but they are walking a very thin line up front.

Celtics assistant Tom Thibodeau seems destined to land one of the NBA head coaching jobs for next season. (AP)

Reports last week indicated that the Hornets were ready to offer their head coaching job to Celtics assistant Tom Thibodeau, and a story by Adrian Wojnarowski at Yahoo!Sports late Sunday night says the team has begun contract discussions with Thibodeau’s representatives at Creative Artists Agency. However, a story out of Illinois’ Daily Herald Monday morning notes that the Bulls have interest in him as well, and multiple reports say that Thibodeau plans to remain in discussions for the Nets job.

Daily Herald reporter Mike McGraw writes that Thibodeau and former Trail Blazers coach Maurice Cheeks are the favorites in Chicago. But the story indicates that Lakers assistant Brian Shaw (a former Celtic) now is being pushed by LeBron James associate William Wesley, who previously was campaigning for John Calipari. The rumor is that James would be interested in playing the triangle offense made popular by Phil Jackson, and Shaw has spent five seasons alongside Jackson learning the intricacies of the offense.

A side note: Creative Artists Agency, with whom Thibodeau recently signed, also represents James and fellow high-profile free agents Dwyane Wade and Chris Bosh.

The Yahoo!Sports report notes that Thibodeau risks losing out on the Hornets job if he decides to wait on the Bulls and/or Nets. Trail Blazers assistant Monty Williams reportedly is the Hornets’ second choice, with some players, including star guard Chris Paul, said to prefer Williams.

A report in the New York Daily News indicated that New Jersey Nets president Rod Thorn might have interest in Celtics assistant Tom Thibodeau for his team’s head coaching vacancy. According to the report, Thorn didn’t mention Thibodeau by name, but he did say he was looking for “somebody who has a defensive presence.”

That description fits Thibodeau, who has been the architect of one of the NBA’s best defenses during his three seasons with the Celtics. Thibodeau has interviewed for several head coaching jobs in the past and many think it’s only a matter of time until he gets one.

The Nets job would be intriguing in that the woebegone franchise finally is moving out of the Meadowlands and the team has a new owner with deep pockets, Russian billionaire Mikhail Prokhorov. Additionally, the Nets have a huge chunk of cap space and two cornerstone players already in place in Devin Harris and Brook Lopez. Also, Thorn is a widely respected executive.

Doc Rivers has been preaching to the Celtics all season long to avoid taking shortcuts on defense and to play with energy and purpose.

He warned that if they didn’t, eventually it would catch up to them.

Well, on Saturday — in a 104-96 stinker vs. the Nets — it didn’t just catch up to them, it barreled them over in stunning fashion on their home court in the form of a 5-52 team beating them soundly and thoroughly.

Perhaps most troubling from the final box score were the 41 free throws the Nets attempted, compared to a measly 11 for the Celtics.

Afterward, there was no hiding for the Celtics coach.

“Like I said before, I still believe in this team,” Rivers said. “I just know for a fact we’re not playing well. But I do believe in this team. But I don’t think you change just to change. I don’t think we need it. I think we need to change our approach and the way we play.

“And tonight you could see it early, even though [at the] beginning of the game we jumped out and after that you just — you know, we had that sense that ‘we’ll get back into it.’ And you know what happened? They actually did try. I thought our guys gave a great effort in the second half, but then they started making shots, and then we’d have the defensive breakdown with three seconds on the shot clock over and over again. Every time we got it down to six or four, a guy would make a 3, a bobbled ball would go to it. I talk about it a lot with our guys: ‘Those are the basketball gods punishing you; you have no right to get back in this game. I thought all those little breaks went to them, and I thought the basketball gods were saying that they deserve to go to you.’ … If you believe in that.” Read the rest of this entry »

The third quarter featured the first energy moment of the game.

With just one second remaining on the shot clock on an inbounds play, Rasheed Wallace caught and fired a three-at the basket that just missed.

Brian Scalabrine rebounded and fired to an open Nate Robinson, who drilled a three of his own with 1:35 remaining and the crowd came to its feet. Moments later on missed shot by New Jersey, Robinson came down and put pack a missed shot and the Celtics were within nine.

But the quarter ended on a sour note as Scalabrine airmailed a three and the Nets led, 74-64. The combination of Courtney Lee and Brook Lopez is killing the Celtics. They have a combined 44 points.