North Carolina had some rhythm on its first drive, gaining as many yards on its first three plays as its next 15 plays. The drive, however, ended by Carolina getting stuffed on third and fourth and one in a sequence that completely changed the momentum and had a major impact on the outcome of the game.
This video focuses on the third down play (we'll look at the fourth down play in the next one). This is a standard RPO where Trubisky counts the players in the box. This play highlights a couple problems that can afflict RPO-based offenses. First, the weather conditions and down-and-distance have an impact on which decision is actually best, essentially changing the arithmetic in situations like this one.
Secondly, Trubisky's primary read is outside linebacker Tre Edmonds on this play, but the Hokies defense is clearly aware of how Carolina's box count rules work here, with Edmunds initially lining up in the box and immediately widening to try to take away the receiver screen. This is Virginia Tech's way of "gaming" the UNC offense into throwing the football while still trying to get an extra player outside to defend that option.
Ultimately, Carolina should have been able to execute this play to gain a yard either way (better blocks on the outside would have helped immensely), but this play still highlights how the weather and a smart defensive approach by Virginia Tech affected UNC's usual offensive approach.