But consider, if you will, how different the mood might be in the aftermath had the Wizards not, as their coach suggested, "just [urinated] down our leg the last six minutes."
Ponder what the overreaction might have been had Kevin Garnett not salvaged the worst offensive performance of his NBA career with stellar defense and hustle down the stretch. Imagine the panic if the Celtics had fallen to the lowly Wizards on their home turf, little more than a week after an embarrassing loss to the even-lowlier Nets in the same building.
The Celtics bailed themselves out by producing six minutes of phenomenal, turn-back-the-clock-to-2008 basketball, which led Washington's Mike Miller to lob verbal bouquets like, "They're a championship team. They've been there, they've done it. We're a young team. When they make their run, especially when they make them at home, you've got to sustain them."
If the Celtics lose, they're an aging, middle-of-the-pack team. After rallying to win, Miller suggested they're championship material.
The Celtics earned the right to take a glass-half-full view of Sunday's win by pulling a 180 over the final 360 seconds, particularly with a defensive effort that showed that maybe, just maybe, this team is still capable of playing at a championship level.
Here's what the Celtics had to like best about Sunday's win: Even with Garnett laboring through his poorest outing since Mariah Carey and Boyz II Men topped the Billboard charts with "One Sweet Day," he never lost sight of what makes Boston tick and produced one sweet defensive effort late in the game.
This came just a couple of nights after Paul Pierce labored through an offensive stinker in Philadelphia, but said he focused his energies on trying to defend the 76ers' top scorer, Andre Iguodala, to atone for his offensive woes.
As Celtics coach Doc Rivers noted after the game, "The offense will take care of itself," but Boston has been built on defense -- team defense -- and that has to be its calling card regardless of how individual players are faring at the other end of the court.
How bad was Garnett's night? Statistics suggest it was the worst of his career as he missed all seven shots he took, settling for eight points on eight free throws (what's more, he missed a pair of freebies in the final two minutes that could have made Boston's rally decidedly easier on the nerves).
Garnett failed to register a field goal for only the fifth time in his career, with the other four times coming during his rookie campaign. He hasn't been blanked since he went 0-for-5 with no points in Minnesota's 104-95 loss to the New York Knicks on Jan. 27, 1996.
Consider this: Of his 1,105 career games, Garnett has been held to eight points or fewer just 54 times (and only 11 times since the 2001-02 season).
Yet, as mightily as Garnett struggled to score, there he was diving for loose balls, setting a key screen to spring Ray Allen, and playing lockdown defense.
Even after Washington's Andray Blatche and JaVale McGee made Garnett look bad at times Sunday, it was Garnett standing within inches of Blatche as time wound down, providing a verbal knockout after enduring all the jabs the rookie delivered as the Wizards built a 13-point lead with six minutes to play.
As Wizards coach Flip Saunders, who coached Garnett in Minnesota, noted, "[Blatche] is woofing the whole time to Kevin Garnett. You can't do those things. It's a learning process. When you're coming up and establishing yourself -- [Blatche] had 23 points with six minutes to go and couldn't hardly get a shot off the last six minutes. You don't take a guy who's been defensive player of the year three times, probably the best power forward, and all of a sudden get that guy juiced up to play against you. You've got no chance."
If Boston's coaches had any worries about Garnett's offense, they were tempered by his play on the defensive end.
"It's funny, [Garnett] never had any balance, offensively," said Rivers. "But there was something I liked and [assistant coach] Armond [Hill] said it during the game. I said, 'Boy, Kevin's struggling a little bit out there.' He said, 'But not on defense.' He looked active. He looked great defensively. He's just out of whack right now offensively. Let's not worry about that. The fact that he has it on the other end, if we've got to take one or the other, we would take that."
Garnett didn't speak specifically about himself, but noted that, as a team, "It ain't perfect." Indeed it's not, but it speaks volumes when a team finds a way to win when it clearly shouldn't have.
And Garnett might as well have been talking about the season as a whole when he noted, "It's not about how you start, it's how you finish. Obviously, we'd like to have had more energy in the first half. You look, we shot 41 percent [for the game], we really didn't play well. But when it came down to getting stops, it was in our favor."
It's unlikely anyone would be nearly as optimistic if the Wizards prevailed Sunday. But after weeks of talking about being able to flip a switch, the Celtics finally showed that they truly might be capable of doing that.
Chris Forsberg is the Celtics reporter for ESPNBoston.com. Follow him on Twitter.