By Cody Westerlund-

CHICAGO (CBS) – In tracing to the roots of the Bulls’ success this season, a familiar narrative has taken shape, becoming a form of gospel for some true believers.

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These Bulls, bless them, lack the talent of the league’s elite, but their possessing of the biggest collection of heart in the NBA allows them to compete with – and their fair share of the time, beat – anyone.

Led by fiery leader Joakim Noah, the creed states, the Bulls on any given night can will themselves to victory by outhustling, outworking and overwhelming foes with emotion. It’s a faith the players themselves outwardly practice.

“Just how hard we play, we don’t give up on any plays,” Bulls forward Jimmy Butler said just a couple days ago. “I can’t say you find that everywhere around this league. But here, if there’s a ball going out of bounds, and somebody is close to it … you’re guaranteed to see a guy dive on the ground or jump in the stands.”

This religion was shared with a national television audience the past two Sundays, when the Bulls did their best to convert Knicks star Carmelo Anthony and then fought off LeBron James and the defending champion Heat with pure grit in the season’s most emotional game.

Of course, there’s another hard truth to all this, the type that only comes to light on a mundane Tuesday night at the United Center with just a local broadcast audience watching to see a team in the midst of a 6-games-in-11-days challenge.

The reservoir of emotional fuel isn’t limitless, as a league-leading San Antonio reminded apathetic Chicago by racing out to an early 32-point lead in an eventual 104-96 triumph. These Bulls can give and give and give, but at some point the tank will be empty, and without a stud, there’s no one to pick them up.

“I don’t take anything for granted,” Noah said after Tuesday’s pummeling, in which San Antonio led at one point 51-19. “This team doesn’t take anything for granted. Just because you usually do it doesn’t mean it happens. You got to go out there and do it.”

So the question remains: How far can emotion take the Bulls, how often can it lead them?

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Although Noah and teammates said Sunday’s emotional roller coaster win over the rival Heat had little effect on Tuesday – “Behind us,” D.J. Augustin said – these games did show the fragility of the Bulls’ stature in the NBA. Chicago (35-29) walks as fine a line as any playoff-bound team, as evidenced by its plus-0.8 point differential, tied for the closest to even in the league.

Just last week, Memphis coach Dave Joerger spoke of the difficulty his injury-riddled Grizzlies have faced in approaching so many games in a loaded Western Conference with a “must-win” attitude. On the outside of the playoff picture looking in, Memphis must have such a mindset.

Chicago has had its DNA infused with a similar mindset ever since Tom Thibodeau took over as coach, but Joerger warned how it can also take a toll on teams with limitations.

“Every game has been so, ‘Holy cow, let’s go get this one’ because you’re playing down three guys,” Joerger said. “Hey, whatever it takes, whatever it takes – guys are playing every single game as hard as they can.

“As far as the importance of every game, much further out than the last 30-game stretch going into the playoffs where, you know, generally the good teams say, ‘OK, it’s time to catch a rhythm here, we got to start playing a lot better basketball’ – we’ve been trying to do that for a long time, and what that does is it can wear you out.”

Not surprisingly, it that mental fatigue that undid the Bulls on Tuesday, when they came out with “no edge,” Thibodeau said, and were thereafter torched by a first-half shooting spree of a Spurs team that again has proved its championship caliber.

“It’s a great lesson,” Thibodeau said. “It’s a great lesson.”

And a sobering one, too, as the “win with emotion” mantra has a ceiling on what’s possible.

It’s called the second round of the playoffs.

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Cody Westerlund is a sports editor for and covers the Bulls. Follow him on Twitter @CodyWesterlund.