After a mostly sleepless night, Dave Odom’s mind was still racing. How had this happened? How had his son and his program pulled this off?

Odom, the former Wake Forest and South Carolina coach, watched from the fourth row in Charlotte on Friday as his son, Ryan, engineered the biggest upset in NCAA men’s tournament history: No. 16 seed Maryland Baltimore County’s 74-54 dismantling of top seed Virginia, the first time a No. 1 seed had ever lost to a No. 16 seed.

“They were forced to change,” Dave Odom said Saturday morning of the Cavaliers, and the interesting thing is that’s precisely what Virginia usually does to opponents.

U-Va. Coach Tony Bennett, one of college basketball’s best tacticians and a man who — in the name of consistency — ignores trends and even the pleas sometimes of his assistant coaches, has turned the Cavaliers into one of the nation’s most formidable programs. Bennett does so using a defensive system known as the Pack Line, as stifling as it is slow-paced and unglamorous, along with specific attacks that have elevated U-Va. into a three-time regular season ACC champion.

But Bennett’s style is so distinctive that, according to coaches intimately familiar with it and those who have pulled off upsets of the Cavaliers, there is — if an opposing coaching staff’s collective ego will allow it — a decided formula to disrupting and even defeating U-Va., and the secret is as simple as this: Play the Cavaliers the way they play you.

“Kryptonite” was how one of Bennett’s coaching peers described the strategy — not much of a secret after U-Va. has fallen victim to its own attacks against lower-seeded opponents in four of the past five tournaments.

“You kind of do to him what he does to other people,” said the coach, who along with others interviewed for this story requested anonymity to honestly assess the strengths and weaknesses of Bennett’s system. “We can’t beat them at our own game, but we can beat them at his game.”

Stifling for both sides

In a sport increasingly trending toward up-tempo play and in a conference with iconic names and personalities, Bennett has set his program apart by being methodical and unwavering. U-Va. — no matter the opponent — is going to play the Pack Line, a variation of man-to-man defense that floods the lane with defenders and forces long and increasingly desperate three-pointers in an attempt to restore a normal rhythm and, simply, to keep up.

It is death by boa constrictor: agonizingly slow, impressively powerful, jarring in how it uses panic as a weapon as the oxygen slips away. It was popularized by Dick Bennett — the U-Va. coach’s father, who used the same strategy to guide Wisconsin to the Final Four in 2000 — and Tony Bennett has spent nine seasons implementing the system, his team’s fortunes living and occasionally dying by it. And the best and worst things about Bennett are his refusal to conform or even adjust.

“I’ve been begging to put a zone in for nine years now. It’s not going to happen,” Jason Williford, a longtime U-Va. assistant coach, said in February during an interview about Bennett’s consistency. “We’re going to do our man-to-man, and these are our principles, and they will work.”

And that last part is true, at least most of the time. The Cavaliers went 31-2 before the NCAA tournament, and in the two losses U-Va. refused to deviate from its typical game plan. Scoring was relatively low, another Bennett hallmark, but West Virginia and Virginia Tech did what the Cavaliers usually do to opponents: put unusual pressure on opposing guards; eliminate or severely limit the opponent’s scoring in transition; use an approach similar to a ball-control ground game in football to reduce the opponent’s possessions and keep the score low. In both losses, Virginia attempted — and missed — an uncharacteristic number of three-pointers.

Michigan State and Syracuse have, in NCAA tournament upsets of the Cavaliers, used similar tactics to surprise U-Va. and end its postseason early. Despite entering three of the past five NCAA tournaments as a No. 1 seed, the Cavaliers have advanced past the Sweet 16 only once.

“You have to guard them the way they guard you,” said a member of a coaching staff that has beaten U-Va. using some of these strategies. “The possession count will be the slowest of any team you play, so your team has to be comfortable with that [and] understand it.”

Another coach added that limiting turnovers and targeting the opponent’s weakest post player with defensive “traps” — other Bennett hallmarks — are key to catching U-Va. off guard.

“You trap their posts just like he does to other people — and it gives those guys fits,” the coach said. “While the rest of the country runs around and tries to score an alley-oop, it’s like: ‘No, we will be different’ — and it fits. ‘I’m going to pressure the guards and trap the bigs and see what I can do.’ ”

On Friday night, U-Va. deployed its typical game plan against UMBC, and though the Cavaliers’ first-half shooting limited their own scoring and hinted at a forgettable offensive performance, the 21-21 halftime score was not atypical of a Bennett half.

Both teams were methodical, and neither seemed to panic. UMBC, which hadn’t so much as reached the NCAA tournament since 2008, remained calm despite the oxygen deprivation. The Retrievers did not try to force a particular style onto U-Va., rather playing the Cavaliers’ game.

“They can’t be sped up,” said the coach involved in a past upset of the Cavaliers, and indeed UMBC wisely did not try to overpower a stronger opponent.

Unleashing his Retrievers

Ryan Odom began unleashing his guards weeks ago, his father said, to apply greater defensive pressure on opponents. It worked.

Almost copying directly from the Cavaliers’ playbook, the Retrievers attacked U-Va. center Jack Salt, who had zero points and four rebounds; desperate and suffocating, the Cavaliers attempted bad shots and increasingly long three-pointers, finishing 4 for 22 from beyond the arc. UMBC committed only 12 turnovers and, for most of the first 30 minutes, did not attempt to hurry the game’s methodical pace or dramatically increase the number of possessions, perhaps learning from other successful Cavaliers opponents who avoided a favorite Bennett trap.

“Those extra possessions are monumental in a negative way,” the member of the coaching staff that has beaten U-Va. said. Turnovers and then 27 seconds of guarding the Cavaliers “turns into bad math quickly that you can’t overcome.”

With about 15 minutes to play, Dave Odom said, he began thinking a historic upset might be possible. The Retrievers had a double-digit lead, the Cavaliers were attempting increasingly long and panicked shots, UMBC kept taking advantage of U-Va.’s poor decisions and turnovers, and the Cavaliers’ defense had long since broken down. U-Va., which had allowed 53 or more points in just 17 of 32 regulation games all season, let UMBC score 53 points in the second half alone.

From across the court, Dave Odom watched his son and the game clock, and when the game ended, Ryan couldn’t have been calmer. He didn’t overreact or do something that’ll get him on the “One Shining Moment” montage, though his Retrievers surely will be heavily featured.

Instead, he methodically congratulated Bennett and conducted a postgame interview with the same enthusiasm as if he had just won an exhibition in November. His father, much more of a reactionary in his day, couldn’t believe it. And though it took him a moment to put his finger on it, Dave Odom thought there was something familiar about the way his son had handled everything about Friday.

“Ryan, I think he is terrific at sharing his confidence with his team,” Dave Odom said. “He’s just really good at that. He stays calm. He’s a lot like Tony Bennett.”