Maybe the C's owe a tip of the cap to the Thunder and Raptors, two teams that shorthandedly beat them this past weekend, capitalizing on their subpar effort?
Maybe they should credit last year's Hawks, who owned them all season and motivated them to get revenge this year?
Maybe a little bit of both. The Celtics had plenty of reasons to dig deep on Monday night and find the motivation to destroy the Hawks. They were on a mission early, and it showed — they got up 39-13 by the end of the first quarter and never relented, burying the Hawks on their home floor by a 99-76 final.
You ask Doc Rivers for an explanation, and it's simple: anger.
"That was the most so far," the Celtics' coach said of his team's "anger level" on Monday night. "I thought after [Sunday] night, they were upset. They thought they were lucky to even be in the game the way they played, and then they gave the game away. That made it even more frustrating. It was interesting this morning — you could just feel it. I didn't know if we were going to win or not, I just knew we were going to compete defensively."
But was it anger at Oklahoma City and Toronto, two teams that caught them napping and stole wins from them over the weekend? Or anger at the Hawks, who manhandled them in four meetings last season? Paul Pierce saw things differently.
"We talked about it, I mentioned it," the captain said after Monday's win. "This was a team that beat us four times. It was sort of like a statement game, I felt like — this might be a team that we play in the playoffs. So during the regular season is a time when you can take away a lot of confidence from teams if you beat them and play them the right way."
Play them the right way? Did they ever. The Celtics completely shut down the Hawks' three best players — Joe Johnson, Josh Smith, Al Horford. All were non-factors from wire to wire. The Hawks' big three entered the night averaging just over 52 points per game; they totaled 14 against the Celtics, who closed out on every shot and gave the Hawks hell defensively.
The Celtics outshot the Hawks in the first quarter, 72.0 percent to 23.5. They outrebounded them 16-3. This game was over as soon as it started.
But rather than pack up shop and go home after the first quarter, as the Celtics have done from time to time with big leads, they kept piling it on this time.
All the cliches apply with this Celtic team — it's about four quarters. It's about 48 minutes. They put it all together in this one.
"It was great," Rivers said. "I was concerned going into the third, obviously, because we know who we've been. And you could see that, but we were pretty engaged right away, so you felt good. So that was good — to extend the lead, get a fourth quarter off, let the second unit play, and even let [rookie Avery Bradley] get some minutes, that was good for everybody."
It was a good night for everybody — from the future Hall of Famers in the post logging double-doubles (17 points and 11 rebounds for Kevin Garnett, 13 and 11 for Shaquille O'Neal) to the rookies just making a first impression (Bradley had two points, a rebound, an assist and a steal in his first six career NBA minutes). It takes a total team effort to beat a contending team by 20-plus, and the Celtics got that effort on Monday.
And as usual, the coach noted, it started with the defense. That's how it's always been with these Celtics.
"We didn't talk about offense at all," Rivers said. "From yesterday to this morning to before the game, I don't even think I said the word 'offense' once. They came in, and you could see their defensive disposition right from the start. It was terrific. And when we play like that, we're a really good team.
"The question is," Rivers added, "can we do it every night? With a veteran team, it seems like at times we start counting how many more games we have to play. So that's going to be our challenge."
Maybe so. But on Monday night, the Celtics reminded themselves what they're capable of when motivated. Now they've got to keep it up.