Despite giving up 187 rushing yards, the Carolina defense played well enough in general to win this game, limiting the Blue Devils to 4.07 yards per carry (down from their season average of 4.54) and a respectable 5.62 yards per play. While not fantastic, those numbers are plenty good enough to win the game, especially given that the offense put up better per-play numbers in each category.
Nevertheless, nearly every game between comparable teams turns on a handful of plays, and this one was no different. In my view, two first half plays were particularly critical: the kickoff return for a touchdown by Duke's DeVon Edwards and the earlier touchdown by Duke's Jamison Crowder on 2nd and 16 in the red zone. (The third-quarter sequence where Carolina missed on three straight deep touchdown passes was also critical.)
The kickoff return came right after Carolina had gone up 15-10 with 1:30 left in the first half, a defensive stop in a two-minute drill situation away from going into halftime with the lead. But yet again, UNC struggled with success, losing fundamentals and giving up a huge play on special teams, entirely changing the complexion of the game going into halftime.
The earlier touchdown by Crowder was especially painful because it came on the heels of two penalties by the Blue Devils that had backed them up into a long-yardage situation in the red zone, a situation that should heavily favor the defense and result in no worse than a field goal.
Instead, Carolina blew the coverage and gave up an easy touchdown. It was a well-designed call by the Blue Devils, but poor coverage fundamentals and recognition in the Tar Heel secondary also contributed to the touchdown.
The basic play is drawn up above, and it's designed to go to Crowder all the way. Duke is in 11 personnel (one tight end, one running back) but with a beautiful twist to create a mismatch: tight end Issac Blakeney is slotted to the left, while Crowder is lined up at the tight end spot in order to get him isolated on a linebacker. The Duke staff rightly guessed that UNC would not match its personnel to get the Ram on the weak side against Crowder here, creating a potential mismatch at each spot.
UNC is in man-under or match coverage with two deep safeties over the top, one of the most popular coverage options in the red zone at any level. The corners are free to play aggressively on the outside while the linebackers play inside-out and protect the middle of the field, with the safeties taking away anything vertical with the aim being to force the quarterback to throw underneath.
Duke, however, knows Carolina's tendencies here and has called a personnel/play package specifically designed to beat this coverage, with a seam/speed out combo to the left side and a "Y-Shake" combo to the short side.
The seam on the wide side occupies the safety to that side, isolating Crowder on linebacker Travis Hughes and safety Tre Boston. Boston's responsibility is to read the releases of the two receivers to his side, staying over top of whichever player goes vertical. He will also have been schooled all week on Duke's most common route combinations in this situation to help him read the route more quickly.
Boston (red circle above) is in textbook position as he reads the outside receiver's release (blue circle) while Hughes shows good technique walling off the dig route. At this point, Boston is almost certainly reading a "smash concept" (one of the most widely used pass concepts at any level) based on the outside receiver's route combined with the vertical release on the inside. Boston expects what you see in the picture below, and you can see his hips begin to turn to the outside.
The Y-Shake, however, is designed to look exactly like a smash until the last second, when the inside receiver breaks inside rather than to the corner. Boston turns to cover the corner route at exactly the moment Crowder plants inside, taking advantage of Boston's understanding of Duke's previous tendencies—and Boston's tendency to get overaggressive. (In Boston's defense, the corner is his bigger priority here, since Hughes is playing inside-out and therefore vulnerable to the outside.)
Duke quarterback Anthony Boone knows he has what he wants as soon as Boston's hips turn outside, as Hughes is helpless against Crowder's speed to the back of the end zone without help over the top, leaving a large passing window in the middle of the field against one of the quickest receivers in the country. (Expect to see Ryan Switzer catch his share of this type of touchdown the next couple years, for what it's worth, as he's a very similar receiver to Crowder.)
This was terrific design by Duke in terms of understanding (and manipulating) defensive tendencies, creating an advantageous matchup, and breaking their own tendency. Boston was a hair overaggressive, but it was for the right reason, as his greater concern is the corner route and he was playing Duke's tendency in this situation. Similarly, Hughes' coverage would likely have been good enough against any Duke player other than Crowder here, but his speed to the post was just too much.
If Carolina's defensive staff had the chance to defend this particular look again, I'm guessing they would want the Bandit to disrupt Crowder a little off the line of scrimmage before rushing the passer and would caution Boston not to turn to the corner quite so quickly—although given Crowder's speed, it's not clear Boston could have supported the inside throw even if he had stayed over the top.
At the end of the day, this particular play wasn't about Carolina making any serious error. Instead, this was good football on both sides (when was the last time one could say that in this series?). Duke's offensive staff just had the chalk in their hand last on a terrifically designed red-zone play.
Photos by J.B. Cissell