BOSTON – Yes, it can be done.

That’s the greatest thing about Boston’s one-year turnaround from a 24-win team to a world champion. In a league where champions normally come from a very short list that almost any pundit could provide months before the season begins, Boston’s immediate U-turn upset the apple cart and reminded the league’s other losers (such as the Nets and Knicks, for instance) how quickly things can change.

Of course, this didn’t happen completely out of the blue. The off-season trades for Ray Allen and Kevin Garnett had everyone pegging Boston as a contender in the East, so it’s not as if the Grizzlies and T-wolves can just sit on their hands this summer and hope for a spontaneous turnaround based on Boston’s example.

Nonetheless, the Celtics’ championship is great for the league, because it sells everyone on the idea that even the league’s doormats can quickly become contenders. While we love dynasties in spots, we also crave uncertainty — that’s what makes the games interesting.

For the NBA, it was the cherry on a sundae of a 2007-08 season. Nearly every thing went right for the league this year, after nearly everything went wrong in 2006-07. Sure, Tim Donaghy keeps popping up at random times like a whack-a-mole, but otherwise the game is healthier than it’s been since Michael Jordan’s second retirement.

At this point, only one thing could be better … a Lakers-Celtics rematch in 2009.

Don’t count it out.

Yes, lots of water can go under the bridge between now and when the Celtics hang banner no. 17 on opening day in November. Remember, a year ago at this time, Allen was a Sonic, Garnett was a Timberwolf, and Doc Rivers was considered a moron.

Even so, both Boston and L.A can make a strong case that they’ll be repeat conference champions next spring.

For the Celtics, it probably won’t be as a team with 66 wins in the regular season. Boston’s intensity over the 108-game grind was the type of thing a team can only sustain once, when everything is new and fresh and fate aligns to give three All-Stars a shot at rewriting their legacies.

Having done that, they’re likely to pace themselves much more a year from now. Garnett will still be his intense, maniacal self, of course, but if Rivers is smart, he’ll dial back the minutes, keep training camp low-key and count on the team slowly building to a crescendo in the spring. Remember, even in this dream season Boston nearly burned itself out early in the playoffs. Without the carrot of a first championship, it’s going to take a lighter touch this time around.

Fortunately, Boston still has a couple of young guys it can count on to help more with the regular-season lifting. Point guard Rajon Rondo was awesome in the Game 6 win — in fact, if the game hadn’t been such a blowout, he might have recorded the first quadruple-double in finals history. The second-year pro still can’t shoot, but he’s so quick and creative that he’s nonetheless established himself as a rising star at the point guard position and should only improve in year three.

In the middle, Kendrick Perkins made similar strides after an injury-plagued 2006-07 season had many doubting whether Boston would get much production from the center spot. His toughness and physicality were a godsend for Garnett, saving much punishment on his wiry frame and helping him survive the long grind at age 32.

And behind Garnett, second-year pro Leon Powe also had a breakout year, one that culminated in his 21-point effort in just 14 minutes in Game 2. He still needs work on D, but his talents as a scorer make him a major weapon off the bench, since the Celtics sometimes struggle to score.

The Celtics have to contend with some potential free-agent losses — Sam Cassell, Eddie House, P.J. Brown, and Tony Allen all can walk, and veterans Cassell and Brown may decide to go out on top and hang up their sneakers. But all these players are replaceable, and as a contending team the Celtics will be a lure for veterans in search of a contender.

So will the Lakers, but they have other problems to deal with. On talent, L.A. figures to be the favorite to win the championship next year. Not only do the Lakers have MVP Kobe Bryant, All-Star forward Pau Gasol, and multitalented Lamar Odom, but they also return 7-footer Andrew Bynum from a knee injury and have a young, improving supporting cast.

The question for L.A. has more to do with motivation and esprit de corps. For starters, the sight of Bryant constantly chastising his teammates in the finals showed that he still has a ways to go in his transformation from me-ball to we-ball. More importantly, Boston thoroughly outhustled the Lakers all series, and L.A.’s shocking capitulation in the 131-92 finale has to leave its management wondering whether a heart transplant is in order.

Phil Jackson alluded to this in his postgame press conference. “We have to get some players if we’re going to … have that kind of aggressiveness that we need,” he said, implying that his current roster is severely lacking in this area.

Of course, Jackson has to look in the mirror himself — he seemed unusually mellow, almost bored, all finals long. At times one wondered if there was a “Weekend at Bernie’s” thing going on and someone was just propping him up on that special high chair he uses — especially after Rivers repeatedly outmaneuvered him.

But a more likely scapegoat is Lamar Odom, who had a poor series and won’t have much of a role to play if Bynum returns and claims a starting frontcourt spot. Odom has a huge expiring contract, which could put him in play for any number of high-price refugees — much as Kwame Brown’s large expiring deal netted L.A. Gasol from Memphis this winter.

Ideally, Odom would be swapped for an upgrade at small forward, where space cadet Vladimir Radmanovic was rather clearly the worst of the 10 starters on the court in the finals. At that position L.A. needs a tough defender who can hit jump shots, sparing them the ravages of players like Pierce at one end and taking the heat off Bryant at the other.

It may take until the trade deadline for that type of player to become available, but if one does the Lakers would be totally unbeatable — no matter how cowardly they looked on Tuesday.

Even without it they look like the class of the West. L.A. was 34-7 in games Gasol played prior to the finals, which is a 68-win pace for a full season. Among the West’s other elite teams, only Utah can claim to be anywhere near the Lakers’ perch.

Unfortunately, they were no match for Boston. We’ll see if things turn out any differently a year from now.

jhollinger@nysun.com