PHILADELPHIA (AP) -- Boston's Big Three hit the Big 5-0.
"It doesn't really mean anything," said Allen, shrugging.
Garnett had 26 points and 12 rebounds to help the Celtics reach 50 victories for the first time in 16 years by beating the Philadelphia 76ers 100-86 on Monday night.
Allen scored 21 points and Pierce had 17 in another stellar outing for The Big Three.
"It doesn't mean a lot. Numbers are numbers," Celtics coach Doc Rivers said. "You don't get a trophy for getting 50 wins. I guess it's nice, but it's not what we're playing for."
The Celtics opened with a 15-0 run, won their ninth straight game and reached the 50-win mark for the first time since they finished the 1991-92 season 51-31.
"They make you realize we have a ways to go," Sixers coach Maurice Cheeks said. "We've been playing well, but we've got to play better. They have seasoned guys, we understand that."
Andre Miller scored 22 points and Andre Iguodala had 17 for the Sixers, who had an eight-game home winning streak snapped. Samuel Dalembert, who complained last week about his minutes and his touches, missed his first eight shots and scored two points.
Miller appeared to hurt his back when he crashed to the court in the third quarter. Miller limped back on defense, but stayed in the game.
The Sixers also lost starting shooting guard Willie Green to a strained lower back in the first quarter, leaving them with an aching backcourt for games this week against Detroit, Chicago and San Antonio.
Sam Cassell made his Boston debut and was whistled for three fouls in his first 3:05. Cassell, signed after being bought out by the Los Angeles Clippers, had not played since spraining his right wrist on Feb. 20 and went scoreless.
"My timing is off. Not knowing the sets, not knowing where to go on the court is tough," Cassell said. "I know I'll play more than 5 minutes. I'm not even worried about it."
No worries on this night. The Celtics had plenty of offensive punch without him.
"It's one of those things where we might have to see them again [in the playoffs] so we wanted to make a statement tonight," Pierce said.
The Sixers honored members of their 1983 championship team at halftime, rekindling memories of when Boston and Philadelphia had one of the fiercest rivalries on the league.
The series has cooled in recent years as both franchises hit down periods, but there was plenty of buzz coming into this one with the Celtics holding the best record in the NBA and the Sixers playing their best basketball in years and a playoff berth in sight.
Perhaps it was a case of big-game jitters, but the Sixers were ill-prepared in front of their first sold-out crowd of the season.
Pierce hit two straight 3s, Allen sank one and Garnett swished a 20-footer to help Boston race to a 15-0 lead.
When Reggie Evans finally sank a free throw with 7:40 left in the first to make it 15-1, he heard mock cheers from a crowd expecting a more competitive start.
"I thought it would stop at some point," Cheeks said. "We got in such a hole, but we battled back to tie it."
Once the Sixers settled down, they shook off their cold touch from the floor and quickly got back into this one. Iguodala hit a 3 that brought them within three points and the Sixers trailed 26-20 at the end of one, a surprising surge from a team that seemed out of it early.
"Up or down, we still keep fighting," Iguodala said.
With the crowd roaring them on with every basket, the Sixers came all the way back and tied the score at 44 on Miller's two free throws with 4:02 left in the half. Garnett, though, hit a 21-foot jumper and a layup to help Boston go on an 11-2 run and lead 53-47 at the break.
Garnett made all five shots from the floor in the half and scored 12 points, and Pierce and Allen were a combined 11-for-16 for 28 points.
The Sixers missed their first nine shots of the third quarter until Jason Smith hit a jumper that cut the gap to 63-52. Philadelphia never got under double digits the rest of the way.
"We're not down. Our sprits are up," Iguodala said.
The Sixers honored former GM Pat Williams, G Franklin Edwards, C Clemon Johnson, C Earl Cureton, F Reggie Johnson, and Cheeks. ... The Sixers are 2-21 when allowing 100-plus points.