Even Bill Russell, Larry Bird and Bob Cousy never were this good this early.
"I've been a big fan of history," Garnett said. "To establish ourselves in that history that's so enriched with culture and prestige and tradition is a great thing."
He finished with 11 points, 12 rebounds and seven assists in three quarters.
Boston's winning streak is its longest since a 14-game run in 1985-86.
Caron Butler scored 19 points for the last-place Wizards, who matched their franchise's slowest start, dropping to 4-16 for the first time since the 1966-67 Baltimore Bullets.
"You saw the best team in the league," Wizards interim coach Ed Tapscott said. "And in case you weren't watching, it wasn't us. It was them."
The Celtics knew what they were playing for. Twice before, including last season, Boston went 20-2 before losing Game No. 23.
"It's always great to be part of a team that's potentially mentioned as one of the franchise's best," Allen said.
Boston had its most lopsided victory of the season -- just as one might expect from a matchup between the reigning champions, who also boast the league's best record, and the woeful Wizards, who have the Eastern Conference's worst mark.
Going into the game, the only thing that might have given Boston pause, and Washington hope, was what happened when these clubs played each other last season: The Wizards took three of four encounters.
"They had our number last year," Allen said, "and we remember that."
Indeed, Celtics coach Doc Rivers said one of his players read something said by a member of the Wizards that drew his team's attention.
Rivers heard his players talking about that before the game.
"It doesn't take them much. I swear they, like, search the newspapers to find something," Rivers said. "I didn't need to give a rah-rah speech."
Washington, though, actually led 12-11 about 4 1/2 minutes in, on a 9-foot floater by Antawn Jamison.
That's when Allen -- and Boston -- got in gear. He completed a four-point play to start a 19-5 run that essentially decided matters, putting the visitors ahead 30-17 with about 2 1/2 minutes left in the first quarter.
Allen scored 13 points in the first quarter with four 3s, combining with Pierce's 10 points to outscore the Wizards all by themselves: The period ended with the Celtics ahead 36-21.
"Just wide open," Allen said.
Washington never got closer than 10 points the rest of the way, trailing by more than 20 for most of the second quarter, which ended with the Celtics up 63-39.
"We're sick of it," Washington guard Juan Dixon said. "We've got to start taking things personal, man."
Clearly, this season's Wizards resemble in no way last season's Wizards.
And what about the Celtics? Are they better than a year ago?
"We don't know yet. That question is yet to be found out," Pierce said. "It's just only a quarter of the season over with. Ask me April 18, and I'll give you a better answer."
That, of course, is the day the playoffs begin.
Notes: Garnett laughed off a postgame question about the white sleeve -- instead of his customary black one -- on his right leg. "It's Washington -- very fashionable, savvy city. I thought, 'Why not switch it up from black to white?"' he said. "Just because I've got a wrap on something -- I've got wraps in places that y'all dont even see." Then, as Garnett walked out of the locker room, he lifted up the bottom of his left jeans leg to show a some sort of white covering on that calf. ... Boston's previous biggest margin of victory this season had been 24. ... Rivers put in the players at the end of his bench for most of the fourth quarter, and what was left of the sellout crowd of 20,173 kept chanting reserve forward Brian Scalabrine's last name, apparently hoping to see him score, or at least shoot. He put up his one and only attempt with 3 seconds left -- and it was blocked.