UNC is set up in a quarters (Cover 4) look with the linebackers and Ram playing zone underneath. Ram Terry Shankle is lined up over Knowles and will read him for his responsibility. If Knowles blocks, Shankle will help in run support. If Knowles releases, Shankle will cover the right flat (from UNC's perspective).
Shankle presses Knowles at the snap, while Stanford releases on a drag route across the middle. Note that Cline stays home to help block defensive end Kareem Martin.
With Knowles releasing up the field, Shankle stays home and watches Rogers, who is chip blocking Bandit Norkeithus Otis in this photo. Stanford continues his drag route while Knowles is roughly 10 yards out from starting his double move (out and up) down the seam.
Shankle covers Rogers as the fullback releases into the flat. Virginia Tech running back Trey Edmunds runs right and chip blocks Martin after play-action. Weakside linebacker Travis Hughes is responsible for the left flat and spies Edmunds at the line of scrimmage. At this point, UNC appears to be in good position defensively.
As Knowles starts his out move with cornerback Tim Scott to his outside, strong safety Dominique Green has latched onto Stanford, although free safety Tre Boston is responsible for the drag route and in place for the handoff.
The double move works as Knowles turns Scott around and has a step on him down the seam. Green has leaked too far over in his effort to cover Stanford. The result, as this photo shows, is two UNC defenders with their backs to Knowles as he races downfield.
Scott quickly adjusts, but Knowles has already beaten him to the inside. Green is too shallow at this point as Boston and cornerback Jabari Price are in position to cover Stanford.
Here's a wide view shot as the ball (circled in blue) is in the air. Knowles has both defenders beat and just needs a solid pass to score the touchdown. Thomas puts the ball on the money and the Hokies jump out in front, 7-0, late in the first quarter.
"It was a well-conceived pass," UNC associate head coach for defense Vic Koenning said this week. "We didn't pass it off as well as we would have liked to to the other safety and then speed turn back out to No. 1. It was more of a technique issue that we work on most every day. We've got a freshman trying the best he can. We've just got to speed turn and get back over the top."