With apologies to Derrick Rose, the Bulls' MVP has been a ferocious D—designed by their rookie coach, a former chucker—that has left opponents feeling suffocated

On the night of March 22 the Bulls filed cheerfully into the visitors' locker room at Philips Arena in Atlanta, having played what appeared to be another perfect game. They had beaten the Hawks by 33 points one day after they clobbered the Kings by 40, and their record was the best in the East. They waited for their coach, Tom Thibodeau, to cough up some praise. But Thibodeau was incensed over a single line in the box score: Jeff Teague, the Hawks' backup point guard, had finished with 20 points, including 17 in the fourth quarter. Thibodeau predicted then that the Bulls would draw Atlanta in the playoffs and that Teague would haunt them because of the confidence they had allowed to grow. The players stifled eye rolls. Teague had been averaging 4.5 points. He erupted only because Chicago's lead was so overwhelming that its starters sat out the final quarter.

Six weeks later the Bulls did draw the Hawks in the Eastern Conference semifinals, Atlanta's starting point guard Kirk Hinrich strained his hamstring, and Teague nearly capsized the Bulls with three 21-point outbursts. Chicago advanced in six games but not without a lesson learned. "Thibs can be a pain in the ass," says Bulls center Joakim Noah. "But he's always right."

How Chicago became the premier team in the NBA, after .500 records and first-round losses in each of the past two years, is largely a testament to MVP point guard Derrick Rose. But Rose has been around since 2008. The difference this season is Thibodeau, a fastidious 53-year-old rookie head coach, who has spent most of his adult life devising ways to keep balls out of baskets. Thibodeau's tightfisted defense is a rugged and rigorous ballet, demanding for those who play it and suffocating for those who encounter it. The Heat, still defined by three individuals, was obliterated by the Chicago Mob in Game 1 of the Eastern Conference finals 103--82 on Sunday. The way the Bulls swarmed LeBron James and Dwyane Wade on the catch and smothered them on the drive made it look as if Chicago had eight players on the court. "This series," says Bulls swingman Kyle Korver, "is what this defense is made for."

The day before the game Thibodeau attempted to deconstruct his system. "Our defense really starts on offense," he says, with a shot taken when the Bulls are well spaced, so three players can rush back to curb a fast break while two crash the boards, then follow closely behind. When the defense is set, as many as four players have a foot in the paint to deter a drive. The defender on the ball angles his body to funnel the driver toward the baseline. The defenders in the post wrestle for inside position as if they're in a jujitsu match. A center or power forward, usually Noah, hollers descriptions of the screens being set in front of him.

The Bulls look as if they are always trapping, but often they are "corralling," bringing over a help defender who stays close enough to home that he can scramble back to his man after a pass. Chicago wants the ball handler, when he glances up, to see a human wall. The aim is for every possession to end in a contested two-point jump shot. The Bulls can run an above-average outside shooter off the three-point line because they are certain help is behind them. The entire scheme is based on a series of synchronized rotations, each player leaving his man to pick up one closer to the ball. Guards are quick enough to make the rotations look easy. Centers have to be just as swift. Thibodeau asks big men to show on a screen at one elbow and then be able to recover to the other by the time a pass can reach his man. "I've heard guys tell him it's impossible," says Bulls reserve forward Brian Scalabrine. "Then he asks them if they could do it for an NBA championship."

The Bulls have the appropriate personnel—muscular guards like Rose and Keith Bogans, long-armed wings like Luol Deng and Ronnie Brewer, hyperactive bigs like Noah and Omer Asik—with the ideal attitude. The principles of the defense, including relentless ball pressure followed by hard close-outs and reliable rebounding, are in no way unique. "What is unique," says one Eastern Conference assistant, "is their energy and intensity. They're the hardest-working team in the NBA by far. They never relax." They are a manifestation of their coach, who is married only to game tape and has no children or outside interests. (He once claimed to have a collection of rare stamps—an obvious lie.) Thibodeau only collects coverages, which he bellows from the bench in his gravelly baritone while crouched in his own defensive stance. "I look at him when he's screaming at the top of his lungs," Noah says, "and I think, This is a hungry dude."

Thibodeau's professional identity is an irony. "Tommy was the worst defensive player I ever coached," says Don Doucette, who coached hundreds of players at six colleges, including Thibodeau at Salem (Mass.) State. "He never bought into the importance of defense. He just wanted to outscore everybody." Thibodeau disputes this depiction—"You have a bad source," he says with a smile—though a different source who refereed his intramural games claims, "If he went to the basket and didn't get a foul call, he'd just hang around and argue until the ball came back across half-court, and then he'd be in position to score."

One of Thibodeau's teammates on the Vikings was Bill Killilea, son of former Celtics assistant coach John Killilea, who coordinated Boston's defense under Tommy Heinsohn in the 1970s. Thibodeau watched NCAA tournament games one night in '80 with the Killileas at a hotel, and John was so impressed by his curiosity that he gave him a copy of "the Bible"—a 200-plus page book outlining his theories on defense, including a radical concept at the time, that ball handlers should be funneled toward the baseline even though more help is available in the middle.

Salem State made Thibodeau its coach when he was 26, and despite a Division III budget and a dearth of video technology, he covered the locker room chalkboard with pro-style scouting reports. "We knew everybody's favorite moves, the plays they ran, the adjustments they were likely to make," says Nate Bryant, a former Viking who played for Thibodeau. "Defense was a science for him. There were never surprises."

Thibodeau left for Harvard after one season, to be an assistant under childhood friend Peter Roby, and he gained access to New England's hoop intelligentsia: Gary Williams at Boston College, Jim Calhoun at Northeastern and Rick Pitino at Providence. By 31 he was in the NBA, an assistant for the expansion Timberwolves under Bill Musselman, who was famous for running 100 different plays, putting his team through 90-minute shootarounds and employing a help defense that tied all five players together like puppets on a string. Thibodeau was on the rise and was so versatile that in 1996 Jeff Van Gundy, then the Knicks' coach, hired him for his offensive insights. "One day I asked him about individual defense, and he started breaking down the stance on the ball, where your hand position should be, how far you should retreat after a jab step," says Van Gundy, now an ESPN analyst. "He gave me a doctoral paper on it. He made me feel bad about my own level of knowledge."

Van Gundy expanded Thibodeau's role to include defense, and in 2000--01 the Knicks set an NBA shot-clock-era record by holding 33 consecutive opponents to fewer than 100 points. But whenever top jobs opened, Thibodeau was ignored. He interviewed three times in 20 years. "It's like politics," says Roby, who became the director of Northeastern's Sport in Society center and is now the Northeastern athletic director. "Teams want to make a splash and win the press conference with a former player or head coach. The grinder, the worker, may not be as charismatic or conducive to the one-liner."

Thibodeau is not part of the Armani coaching tree. Doucette visited him in apartments around the country decorated with nothing but cardboard boxes and game tapes. "Tommy, there are only so many ways to defend a pick-and-roll," Doucette would say, and Thibodeau would go searching for one more. He returned to Boston in 2007, to be defensive coordinator for Doc Rivers, just as Killilea was for Heinsohn. In his first training camp he grabbed a couple of Celtics by the jersey to show them where they needed to be in a drill. The fear of many general managers, that Thibodeau would alienate NBA players with his direct style, proved to be unfounded. Boston became the best defensive team in the league, and last summer Thibodeau was finally rewarded with offers from the Hornets and the Nets.

"You've waited so long," Van Gundy advised him. "Just take one." Thibodeau scouted each organization as if it were an opposing offense. He worried about the unsettled ownership situation in New Orleans (the team was later sold to the league) and the future of president Rod Thorn in New Jersey (he bolted to the 76ers). Thibodeau held out for the Bulls, who offered him the job the day after they interviewed him. A few weeks later, as general manager Gar Forman sat in his office at the team's practice facility, he heard the lights flick on over the court behind him. It became the sound track of the summer.

Thibodeau led his players through a procession of exhausting individual workouts, many twice a day, some late at night. "I'd hide from him, and he'd still find me," Noah says. "I'd tell him, 'Thibs, I can't do it again, I'm tired, it's summertime, it's Friday, let's take it easy, let's chill.' He didn't go for that." Thibodeau flew to Las Vegas for Team USA's training camp, just so he could talk to Rose after practices, and even though Thibodeau did not travel to Turkey for the world championships, he and Rose chatted on the phone after games. Forman suggested that Thibodeau forget about buying a house in Chicago and simply build a third story on top of the facility.

The Bulls were initially wary of their Belichickian leader, who gave them scouting reports as thick as suburban phone books and put them through shootarounds that always started at 10 a.m. and ended at exactly 11:15. Noah needled him about the interminable mornings—"Thibs, we have a game today, let us get off our feet"—to which Thibodeau responded, "Do you like to win?"

The Bulls led the NBA in defensive efficiency, rebounding differential, opponents' field goal percentage, opponents' three-point percentage and, according to hoopdata.com, opponents' field goal percentage from three to nine feet. They demolished inside and out. Miami forward Chris Bosh went 1 for 18 in a game against the Bulls, the worst shooting percentage by a player with that many attempts in 38 years. Jazz point guard Deron Williams grew so frustrated against the Chicago D that he changed a play ordered by coach Jerry Sloan, an audible that precipitated Sloan's resignation and Williams's trade to the Nets. The Pacers scored 17 points in the fourth quarter of a January game against the Bulls, and the next day coach Jim O'Brien was fired. De-fense chants, a staple of every NBA arena, echoed a little louder at the United Center.

"How often did you watch us this year and think, They didn't play hard tonight?" Deng asks. "That's because of Thibs. We see how much he pours into it." The Bulls eye their Coach of the Year on charter flights, face illuminated by his laptop, scribbling notes. Thibodeau studies the Bulls and their upcoming opponents, of course, but also the patterns of individual players around the league. "He figures out what guys do to get themselves going, and then he tries to take that away through adjustments," Scalabrine says. "It's psychological warfare." Scalabrine is not referring simply to the sweet spots on the floor where players go for their shots but also to the different ways they ease themselves into games. Some, like Hawks guard Jamal Crawford, want to immediately free up for open threes. Others, like James, prefer to hand out a few assists before even thinking about scoring. Thibodeau aims to break their rhythm and limit their confidence, which is why he was so irritated about Teague.

Chicago's defense is constantly changing based on all the accumulated intelligence. "When you're dealing with special players, you have special rules," Thibodeau says. In Game 1 against the Heat, the Bulls did not double James early and thus took away openings for the highlight passes he craves. They did, however, corral him with a help defender. For all its quickness and length Chicago can still be susceptible to teams that swing the ball around the perimeter, but the Heat continued to isolate James and Wade. That's why the Bulls are so well-suited to win this series and reach the Finals for the first time since the Jordan era. James and Wade may be two of the best one-on-one basketball players in the world, but they are going one-on-five now, dribbling headlong into the teeth of some very hungry dudes.

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"HOW OFTEN DID YOU WATCH US AND THINK, THEY DIDN'T PLAY HARD?" ASKS DENG. "THAT'S BECAUSE OF THIBS. WE SEE HOW MUCH HE POURS INTO IT."

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Photograph by GREG NELSON

GLASS ACT Thibodeau (above) stresses limiting opponents' second chances, which Noah and the Bulls did in Game 1, holding the Heat to six offensive boards.

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HEINZ KLUETMEIER

[See caption above]

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HEINZ KLUETMEIER (JAMES)

O.K., CORRAL Chicago swarmed Miami's one-on-one aces on Sunday: Rose (1), with some help, cut off Wade's drives, while Kyle Korver (far left) and Deng kept James bottled up.

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GREG NELSON (WADE)

[See caption above]