CHARLOTTE, N.C. — Few teams beat Duke.

That’s just the way it has been in college basketball the past two decades. This season, just four teams have done it, including North Carolina, the Blue Devils’ biggest rival.

This is the job the Michigan basketball team faces today (2:45 p.m., CBS) as it tries to end Duke's season and advance to the Sweet 16 in the NCAA tournament.

So how did North Carolina beat Duke, 81-67, on March 5?

“When you prepare, you have to pay attention to very, very small details,” Carolina guard Justin Watts said. “There is a very fine line between beating Duke and losing to Duke.”

Let the Tar Heels explain in some not-so-easy steps:

Force Nolan Smith to the sideline While Michigan would love to get the ACC Player of the Year and probable first-team All-American sidelined with foul trouble, the senior guard is usually too crafty to allow that to happen.

North Carolina’s players said that Smith likes to do most of his work in the middle of the floor, from creating for others to letting go jump shots as he averages 20.9 points, 5.3 assists and 4.5 rebounds a game.

“One of the keys would be keep him out of the middle of the court,” Carolina senior D.J. Johnston said. “We stressed sideline position, and if you can get him to go down the sideline, that’s ideal. But there’s only so much you can do.”

North Carolina tried using its point guard, Dexter Strickland, against Smith. When the Tar Heels beat Duke, they were successful. In last week’s ACC championship game, a 75-58 Duke victory, they weren’t.

“He likes to get his shot off in the middle of the floor,” Strickland said. “So everybody just being ready for the drive and having supportive defense is the key to stopping them.”

Michigan guard Darius Morris might find some opening in the Duke defense on Sunday.

Jake Drake | Icon Sports Media

Attack Duke likes to spread out defensively, which opens lanes allowing possible penetration for guards.

This might play well for Michigan and Darius Morris, a point guard who feeds off penetration.

“Their defense is spread out so if you attack and somebody rotates over, (we) could dish it to (Tyler Zeller) or John (Henson),” Strickland said. “I think that’s what we did well when we played them in Chapel Hill so that’s the key to attacking them.”

The pick-and-roll, which has become a Michigan offensive staple this season, might not be as effective, though, because Duke is familiar with defending it due to their offensive principles.

Reaching the point of driving the ball isn’t easy to get to, either, because of the way Duke defends.

“They’ll pick you up, sometimes three-quarters court,” Johnston said. “The last game we played against them, in the ACC tournament, they really took us out of (things). We were starting our offense around half court. They’ll pressure you a lot. The key is to not stop when you get over half court, which tends to be a lot of people’s tendencies, like the 10-second count is off, I can relax.

“It’s just they are a nose to the grindstone in their defense. Whether it is fear of their coach or a want-to that other teams don’t have, they are good at it.”

Box out everyone Michigan coach John Beilein joked Friday his team had boxed out everything they saw in the last week to prepare for Tennessee.

If the Wolverines want to win Sunday, they’ll have to do that even more than they did against the Volunteers, when they outrebounded them 36-26.

One of Duke’s strengths is grabbing boards as four Blue Devils average more than 4.5 rebounds a game, led by Mason Plumlee with 8.4.

When Duke gets a second chance in a possession, it is often deadly for an opponent.

“The biggest thing is that you have to keep them off the boards,” Carolina forward Tyler Zeller said. “Their bigs do a great job of getting offensive rebounds and then they’ll kick it out to shooters and it is three points instead of two.”

Duke has been averaging three more rebounds than its opponents this year.

Play your finest defense That might sound silly, but every Carolina player said when they beat Duke, they played their best defensive game of the year.

They rotated well on Smith, contained role players like guards Andre Dawkins and Seth Curry and the Plumlee brothers, Miles and Mason.

“We just played great team defense,” forward Justin Knox said. “When Nolan and Kyle (Singler) get the ball, they are always looking to drive and we, for the majority of the game helped off, helped each other when the person was driving and just made great stops the entire game.

“It was a total team defensive effort the whole game and it was pretty much the main reason why we got the W.”

At the same time, Michigan players need to understand no matter how much they try to stop Smith and Singler, they are going to score and get their share of points. And with the dribble-drive offense, Duke just waits for an opponent to make a mistake.

Then the Blue Devils quickly take advantage and score.

“They space you out and make you make a mistake on defense, which is a good strategy,” Knox said. “You have to be able to guard the ball by yourself, not require a lot at help. And attack back at them.”

The Kyrie factor Of course, North Carolina beat Duke without Kyrie Irving, the freshman point guard whose toe has received as much attention as any full-bodied person this week. Irving’s return gives the Blue Devils another playmaker, another scorer and another All-American.

So that makes it all even harder.

Michael Rothstein covers University of Michigan basketball for AnnArbor.com. He can be reached at (734) 623-2558, by e-mail at michaelrothstein@annarbor.com or follow along on Twitter @mikerothstein