They relied on little else down the stretch during the 2010 postseason, overcoming old age and a banged-up roster to nearly steal a title that very few even had them playing for.
The truth is, though, part of the reason most didn't peg Boston for the Finals was a sheer lack of effort in the regular season.
Yes, there were injuries. Kevin Garnett hyperextended his already-balky knee. Marquis Daniels missed more than a month with a torn thumb ligament. A series of injuries kept Tony Allen on the bench for more than a third of the season. Glen Davis and Paul Pierce missed time, as well. At one point, Doc Rivers called Andrew Declercq and Dino Radja to see if they could fill in some minutes (Alright, I made up that last part).
A bit of a let-down under those circumstances is understandable. And yet, the C's took their feet completely off the proverbial pedal.
They went 6-8 in the month of January and 7-5 in February before losing seven of their final 10 games of the regular season. All this as Boston fought for home-court advantage in the playoffs — a battle they lost, finishing fourth in the Eastern Conference and seven games back of Los Angeles in the NBA-wide standings (Give the C's that 13-point lead in the third quarter at the Garden, and my guess is the Lakers don't come back).
The point is, the Celtics mailed it in during much of the 2009-10 regular season.
Nothing like new faces and a healthy dose of competiton at a number of key spots to turn that around.
1. The Centers
Shaquille O'Neal can say it a million times. I just want to win. I don't need to start. Whatever the team needs. But the reality is, Shaq wants to be on the floor first. And so does teammate Jermaine O'Neal.
Both have shown up to camp fit and gunning for the No. 1 spot. While Doc has said J.O. will likely begin the season as the starter, the 31-year-old center is now hampered with a hamstring injury, and Shaq ran with the first unit the last couple of days of training camp in Newport, R.I. Rivers, in fact, called the 38-year-old superstar the "biggest surprise" of camp.
Either way, both should be fighting for more minutes every time they step on the floor — a good change of pace for two guys who showed lackluster effort last season.
And don't forget Kendrick Perkins, who bluntly told reporters at media day last week that his position is his alone.
"I really don't want to answer that question, because I don't want to start nothing," Perkins said, "but really my spot is not up for grabs. When I come back, I will be in my spot. Everyone else will just have to adjust."
2. The Guards
Boston is more stacked at the point – and shooting guard positions than it has been in a long time, prompting Doc to call it "the best bench we've had since I've been here, on paper." Delonte West and Avery Bradley back up perhaps the best point guard in the game, Rajon Rondo, with Nate Robinson and Von Wafer available to spell Ray Allen at the 2-spot.
While Robinson has spent the last few weeks establishing a valuable rapport with his teammates, Wafer says he's in a "dogfight" for the 15th roster spot with camp-invitee Mario West, who Doc has said "could be a defensive stopper" to replace T.A.
And though West (suspension) and Bradley (ankle) will miss the start of the season, both have impressed just about everyone with their work ethic. All this as Rondo has made it clear that at season's end, he wants to be recognized as the best point guard in the league, saying "I'm the best, hands down. There's no speculation. Not top three or top five — I'm the best."
3. The Outsiders
Bradley, Luke Harangody, Semih Erden and camp invitees Mario West and Stephane Lasme have also provided a spark as they battle for roster spots (West and Lasme, in fact, are likely to be cut) and playing time. Bradley and Erden stayed late at practice Monday, while Doc called West "a great energy guy."
Harangody, meanwhile, has worked non-stop since Draft Day to ingratiate himself into the organization, putting up impressive numbers in summer ball before a solid showing at camp.
The result of all these mini-competitions is a more general sense that this year's Boston team simply has more fire in it. They seem healthier, happier. They joke more with one another. And perhaps most important, they appear to be working harder, too.
"Very competitive," KG described camp in a phrase. "What I love about Doc is that he doesn't mind us being competitive as long as we don't go off on our own and practice doesn't become a tropical storm. But he lets us be who we are ,and it does get testy and very competitive in here. But he lets us go, as long as we're getting something done and our goals are met for the day."
Perhaps, in the end, that competitive spirit will help the Celtics meet their ultimate goal, as well.