Theo Pinson’s game-clinching dunk came after a strategic lapse we’re not used to seeing from Mike Krzyzewski-coached teams. (Streeter Lecka/Getty Images)

For as much hype as the two (and sometimes three) annual meetings between Duke and North Carolina receive, they usually aren’t great ways to learn about either team.

By the time the heavily scrutinized Tobacco Road rivals clash each season, they’re both known commodities: The first leg of the regular season home-and-home series is entrenched in early February (it was last played in January in 1999 and before Jan. 27 in 1991). The second meeting sits on the final weekend before the ACC tournament.

North Carolina’s 82-78 victory in Chapel Hill on Thursday night fit the pattern, especially in the case of Duke. What unfolded was far less revelatory than it was an exercise in reinforcement. North Carolina’s strengths, some of them a bit underappreciated, helped the Tar Heels win Round 1. And Duke’s vulnerabilities received a new look, though they weren’t as glaring as in Saturday’s loss at St. John’s.

The Tar Heels’ offensive rebounding carried the day.

Much has been made about North Carolina and Duke flipping identities this season. This is a Tar Heel team without dominant interior presences (such as Brice Johnson, Isaiah Hicks and Kennedy Meeks in recent years), and Duke is less perimeter-oriented thanks to freshman big men Marvin Bagley III and Wendell Carter Jr.

But what’s been underappreciated all season is North Carolina’s offensive rebounding even as Coach Roy Williams shifted away from fielding a lineup with two traditional bigs. Entering Thursday, the Tar Heels ranked 11th in the country in total offensive rebounds, with just two power-conference teams (West Virginia and Duke) ahead of them. Coming out of Thursday, ranks North Carolina at No. 3 in offensive rebounding percentage (38.4 percent).

That’s down a tick from the last two years, but grabbing 20 offensive rebounds (to Duke’s 27 defensive rebounds) on Thursday didn’t come out of nowhere. Cameron Johnson had six, and freshman Garrison Brooks had four in 12 minutes off the bench. Both of those numbers will leave Williams ecstatic, especially since it forced Duke to play more defense than it should have in the second half.

Cameron Johnson and Kenny Williams are North Carolina’s difference-makers.

To be sure, they’re not the Tar Heels’ best players. Senior guard Joel Berry II is among the most tested and accomplished active players in the college game. Forward Luke Maye has fashioned himself into a nightly double-double threat.

Johnson and Williams are the bellwethers, though. Williams matched career highs in points (20) and three-pointers (six) in the defeat of the Blue Devils. When he reaches double figures in scoring, North Carolina is 15-2. When he doesn’t, the Tar Heels are 3-5.

Johnson’s also an interesting variable. He was a proven ACC player when he hit the grad-transfer market as part of the exodus out of Pittsburgh after last season. He lost the first five weeks of the season to injury and didn’t enter the starting lineup until four games into conference play. But if he’s both hitting outside shots and providing a defensive lift, it adds a dynamic to the Tar Heels. Johnson had 18 points, 13 rebounds and four three-pointers Thursday.

When Duke loses, Trevon Duval usually struggles.

When the Blue Devils upended Michigan State at the Champions Classic in November, Grayson Allen was the center of attention for scoring 37 points. That’s life for a guy who spent the last year or two as college basketball’s biggest lightning rod.

But for those really paying attention, the striking development was the Blue Devils finally had a replacement at point guard for Tyus Jones, who turned pro after helping Duke win the national title in 2015. Duval had 17 points, 10 assists and six steals against Michigan State, and even with three turnovers and a few missed free throws, he made this Duke team different.

Move ahead to Thursday, when Duval had nine points, five assists and four turnovers. He logged only 20 minutes before fouling out. Duval’s averages in Duke’s five losses: 10.8 points, 5.8 assists and 4.6 turnovers. Teams don’t last long in the postseason when their point guard produces stat lines of those sorts.

Duke needs more from Allen, too.

Weird as it sounds, Allen is Duke’s Kenny Williams. The Blue Devils are 16-1 when Allen reaches double figures, 3-4 when he doesn’t. It should be noted that Allen was far from Duke’s biggest problem Thursday — he had nine points and seven assists against just two turnovers in 40 minutes, though he was 2 for 8 from three-point range.

After an exceptional sophomore year, Allen didn’t come close to meeting outsized expectations last year (and his own on-court behavior played a role, to be sure). This Duke team doesn’t need him to average 20 points, but it does need him to be steady and stable. In the Blue Devils’ five losses, Allen is averaging 8.6 points while shooting 26.4 percent from the floor. That won’t cut it.

North Carolina played close to its peak in the second half.

The Tar Heels’ resolve last season reflected how close it came to winning on the final day of the season the year before. That’s hard to duplicate without a miserable memory gnawing at a team, and even more difficult when the program got to enjoy a victory lap after winning last year’s national title.

It’s a problem any program would happily take. Nonetheless, this North Carolina team is a bit erratic. In the second half — when it grabbed 15 offensive rebounds, committed just one turnover and held Duke to less a point per possession — it reached a level it rarely has this season. The question now is whether the Tar Heels can duplicate this showing outside the crucible of the Duke-UNC rivalry.

Duke’s late-game decision-making is subpar.

North Carolina sealed the victory when Theo Pinson delivered a transition dunk with 11.1 seconds left, bumping the Tar Heels’ margin to 82-75. It came about nine seconds after a North Carolina steal. It’s stunning a Mike Krzyzewski-coached team trailing by five points in the final 30 seconds would let that much time elapse without fouling.

Well, except for the fact Duke didn’t handle the closing seconds of Saturday’s loss at St. John’s with distinction, either. Down three with about 33 seconds left, Duke didn’t immediately look for a quick two, instead settling for a three-point shot before getting fouled while grabbing the rebound. On the next possession (down three again), Duke again took its time before missing another three-pointer (though St. John’s played superb defense on that possession).

Krzyzewski’s teams historically have been exceptional (in the rare cases when it was necessary) at extending games and forcing other teams to do themselves in. This one isn’t — and is now 1-4 in games decided by five points or less.

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