Duke's Kryptonite Readily Apparent on Eve of 2017 NCAA Tournament

In a fantastic capstone to a wild ACC regular season, No. 5 North Carolina emerged from Saturday night's back-and-forth battle with No. 17 Duke with a 90-83 victory.

"Coming in, we knew we were the ACC regular-season champs, but we wanted to do something for ourselves," North Carolina point guard Joel Berry told ESPN's Maria Taylor after the game. "We wanted to get revenge [for Duke's win on Feb. 9]."

Berry was on fire in the first half, scoring 19 points while draining each of his five three-point attempts. He finished with a team-high 28 points.

But the biggest difference from the first game—both literally and figuratively—was Isaiah Hicks. UNC's senior power forward missed the first game with a hamstring injury, but he had 21 points and a game-high nine rebounds in just 22 minutes of action. If he can somehow manage to stay out of foul trouble, North Carolina looks like the clear favorite to win the national championship.

Now, normally when these teams square off, we enjoy the spectacle, talk about how much fun it was and then forget about it. You throw out the record books when they get together and you ignore the stat sheets after the game. Trying to glean any forward-looking analysis from a rivalry game is almost always a fool's errand.

This one feels different for Duke, though.

It was more of an omen of what's to come at some point in the NCAA tournament.

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Teams with multiple interior scoring threats have been giving Duke fits all season long. When Kansas shot 31-of-48 from two-point range and out-rebounded the Blue Devils 38-29 way back in November, we let it slide. After all, help was on the way in the form of Jayson Tatum, Harry Giles and Marques Bolden, right?

Things haven't gotten any better, though.

By now, Duke was supposed to have the deepest and most dominant frontcourt since that Karl-Anthony Towns-led five-headed monster Kentucky had two years ago. Instead, Bolden has barely touched the floor in the past six weeks, Chase Jeter has been out since mid-January with a back injury, and Giles still looks like he has no clue what he's doing on either end of the floor.

Tatum is 6'8", but he's a wing-forward who's more of the former than the latter. He'll grab a decent number of defensive rebounds in every game, and he has excellent footwork on the defensive perimeter, but he's a bit out of his element against a back-to-the-basket big man.

Save for the limited minutes Giles and Bolden play, this leaves Amile Jefferson as Duke's only true frontcourt defender. Credit where it's due to the fifth-year senior, he has been outstanding in that role. The Blue Devils are far from elite in defensive rebounding and two-point field-goal defense, but they're marginally above average in both of those areas because of Jefferson.

However, he's only one man, and teams are capitalizing on that.

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According to KenPom.com, opposing teams are scoring 59.9 percent of their points against Duke on two-point field goals, which is the fourth-highest rate in the country. After factoring in North Carolina's 28-of-50 night, the Blue Devils are allowing opponents to make 48.4 percent of their two-point attempts.

But that includes blowouts against the likes of UNLV, Marist, Appalachian State and Maine, teams that could not buy a two-point bucket to save their lives. In all but one of their eight losses—the 55-50 mutual brick-fest against Miami—the Blue Devils have allowed their opponents to shoot at least 52.5 percent from inside the arc.

Opponent	2PM	2PA	2P%
Kansas	31	48	64.6
Virginia Tech	24	45	53.3
Florida State	30	52	57.7
Louisville	21	40	52.5
N.C. State	23	41	56.1
Syracuse	19	36	52.8
Miami	21	50	42.0
North Carolina	28	50	56.0
Average	24.6	45.2	54.4

To put that number in context, when Duke won the national championship in 2015, its opponents in the tournament shot a combined 41.8 percent from inside the arc. Gonzaga was the only one to fare better than 45.0 percent, and even the Bulldogs only went 20-40 (50.0 percent) with a front line of Kyle Wiltjer, Domantas Sabonis and Przemek Karnowski.

When Duke's offense is firing on all cylinders, this kryptonite becomes more of a minor inconvenience. North Carolina made 28 two-pointers in the first game, but it didn't much matter because the Blue Devils drained 13 of 27 from beyond the arc. They also shot 13-of-27 against Wake Forest a few weeks ago, winning by a slim margin after allowing the Demon Deacons to make 30 twos.

Duke was just 7-of-19 from downtown in round two against UNC, though, and grabbed three offensive rebounds in the first 32 minutes. It's only because they got to and converted from the free-throw line so many times (28-of-35) that this thing wasn't a blowout.

So, what happens if the Blue Devils draw a first-round opponent like Middle Tennessee—a team that plays at a methodical pace and does most of its damage on two-point buckets? What if they run into a frontcourt wrecking ball like Purdue's Caleb Swanigan or Seton Hall's Angel Delgado in the second round? Or could you even imagine Jefferson trying to contain Gonzaga's entire front line of Karnowski, Zach Collins and Johnathan Williams III?

The Blue Devils might get lucky with their draw for a little while, but they're going to eventually run into a team that can exploit their frontcourt weakness.

People have been saying for decades that Duke lives and dies by the three-pointer. That will likely need to be the case multiple times in order for Mike Krzyzewski to win his sixth national championship.

Kerry Miller covers college basketball for Bleacher Report. You can follow him on Twitter: @kerrancejames.