LOS ANGELES — In their comeback season, the Celtics saved the biggest one of all for the NBA finals.

Boston rallied from a 24-point deficit and beat the Los Angeles Lakers, 97-91, last night to take a commanding 3-1 lead in this history-rich series and move within one victory of a 17th championship that seemed impossible a year ago.

A rivalry between the league's two most storied franchises — with some of the game's biggest names and biggest moments — now has its biggest rally.

No team had ever overcome more than a 15-point deficit after the first quarter, and Elias Sports Bureau said it was the biggest comeback in the finals since 1971. One thing's for sure, it will forever be remembered in the annals of Celtics-Lakers lore.

When the final horn sounded, Paul Pierce, an L.A. kid playing in front of family and friends, doubled over in exhaustion and exuberance. The Celtics, the team he stuck with through 10 years, including a 24-win season in 2006-07, had done the impossible.

"We sucked it up," Pierce said. "We said we weren't going to back down.

"At the end of the third quarter I looked up at the scoreboard and told the fellas, 'We just have to go out there and compete and let the chips fall where they may.' "

Pierce scored 20 points, Kevin Garnett had 16 points and 11 rebounds and Ray Allen had 19 points as Boston's Big Three, thrown together last summer by general manager Danny Ainge to revive a franchise accustomed to hanging banners from the rafters, put the Lakers on the brink of a summer vacation.

It took an epic comeback to do it, and now the Celtics can reclaim their place atop pro basketball with a win in Game 5 Sunday night in Los Angeles.

No team has ever recovered from a 3-1 deficit in the finals.

"It can always happen. We aren't counting on that statistic," Pierce said. "We want to take care of this on Father's Day."

Kobe Bryant scored 19 points on 6-of-19 shooting but the league's MVP couldn't rescue the Lakers when they needed him most. Lamar Odom had 19 points — 15 in the first half — and Pau Gasol, whose addition in a midseason trade was supposed to give the Lakers their final piece to complement Bryant, had 17 points and 10 rebounds.

Trailing by 18 points at halftime and seemingly done when they fell behind by 20 with 6:04 left in the third quarter, the Celtics outscored the Lakers 31-15 in the third quarter to pull within 73-71 going into the fourth.

The remarkable rally was reminiscent of what Los Angeles did in Game 2, when the Lakers trimmed a 24-point deficit to two in the fourth quarter before the Celtics regrouped to open a 2-0 lead. But Boston had another 12 minutes to finish off theirs, and the green-and-white did.

Boston's comeback included a 21-3 run over the final five minutes of the third quarter, fueled by two 3-pointers from Eddie House, who was getting more playing time because of Rajon Rondo's tender left ankle. The Celtics were still down by double digits with 2 minutes left in the third but closed the quarter with a 10-1 run, capped by P.J. Brown's dunk — a slam that could be felt all the way back to Boston's North End.

The Celtics finally caught the Lakers at 73-all on Leon Powe's jumper in the lane with 9:05 remaining, tying the score for the first time since it was 2-2 in the first minute.

At that point, the Lakers looked lost, confused, you name it. And when House hit an 18-foot jumper with 4:07 remaining, the Celtics had their first lead, 84-83. Boston's bench erupted, Lakers fans gasped and it was just a matter of time before they were heading out of Staples Center wondering what went wrong.

Bryant, who except for a 36-point performance in Game 3 has been an ordinary superstar in his try for a fourth championship ring, tried to rally the Lakers and got them within 89-87 with one of his patented twisting layups. But James Posey drilled a 3-pointer for Boston to make it 92-87 with 1:13 left. Derek Fisher's long jumper got the Lakers within three.

But Pierce was fouled and made two free throws, forcing Los Angeles coach Phil Jackson to call a timeout with 47 seconds to go. As the Lakers headed toward their bench, Pierce pumped his fists, flexed his muscles and let out a yell.

Surrounded by Hollywood stars on their own back lot sound stage, the Lakers were seeking their 10th straight win at home in the postseason and were about to drop the "if necessary" tag from Game 6. Now, they have to hope they can force the series back to Boston.

For the third time in this series, commissioner David Stern met with the media before the game. It was an unusual step for the league's long-tenured leader, who went on the offensive to defend the integrity of NBA officials under fire in the Tim Donaghy scandal.

Maybe the next investigation should focus on what happened to the Celtics in the first quarter.

L.A's crowd, notorious for arriving late, leaving early and spending more time text messaging and talking on cell phones than clapping, was much more involved than in Game 3. They roared when Lakers Hall of Fame center Kareem Abdul-Jabbar presented the game ball to officials and were on their feet when Los Angeles blasted to a 16-6 lead.

By then, Odom had scored eight points, doubling his total from Game 3 and the enigmatic forward finished the first quarter having made all six field-goal attempts and scoring 13 points. Moments later, Garnett went out with his second personal, and with the NBA's best defender on the bench, the Lakers ran wild.

Odom made consecutive jumpers from the top of the key to put Los Angeles ahead 26-7. The Lakers eventually pushed their lead to 45-21 when Sasha Vujacic, whose 20 points sparked his team in Game 3, nailed a 3-pointer and it was the Boston Massacre, West Coast style.

But the Celtics wouldn't quit.

"Once we got the lead, obviously, we were thrilled to death," Celtics coach Doc Rivers said. "As far as we were down, nothing was going right for us, and we just hung in there."