As the Hokies prepare to face the defending national champion Clemson Tigers, a red-hot spotlight will be on redshirt freshman quarterback Josh Jackson. Jackson has put up numbers that are garnering national attention.

Jerod Evans & Josh Jackson had never taken an FBS snap before starting at VT. Their stats since start of '16 essentially = Mason Rudolph. pic.twitter.com/tzm7xiWAl6— #DaHale (@DavidHaleESPN) September 24, 2017

#VaTech FR Josh Jackson is completing 77%, has an 8-0 TD-INT ratio & has the nation's top QB rating (264.4) in the second half this season.— Bruce Feldman (@BruceFeldmanCFB) September 24, 2017

At the same time, Jackson has faced some pedestrian defensive units, and has exhibited some struggles especially early in games. Clemson's defense, anchored by the best defensive line in college football, poses a huge challenge for the green signal caller.

Old Dominion provided Jackson with at least a high-speed simulation of Brent Venables' vaunted defensive attack. Clemson blitzes from all angles, has fast defensive ends who like to get up the field, and switches coverages behind pressure. Unlike West Virginia's boom-or-bust blitzing, or Delaware and East Carolina sitting back passively, the Monarchs mixed in tight man-to-man and some zone blitzes to confuse Jackson.

No single pass pattern has been more effective this season for Virginia Tech's offense than the post-flat combination. While the Hokies can call the slant-flat from multiple formations using both drop back and play-action, several elements are consistent.

On this third-and-two variation, there is no play-fake. Chris Cunningham motions across the formation. To the field-side, Old Dominion safety Sean Carter (No. 31) flexes out with Cunningham. That indicates to Jackson that he has man coverage. At the snap, running back Deshawn McClease heads to the left flat. Cam Phillips runs a skinny post.

Jackson has one read on the play, OLB Jordan Young (No. 32). If Young runs up on McClease, Jackson throws to Phillips. If Young sinks on Phillips, Jackson throws to the flat. In this case, Young charged forward on McClease. Jackson trusts that Phillips can beat man coverage. The throw is quick so it can beat the five-man pressure from the Monarchs. Jackson is accurate and Phillips generates extra yards with his legs; a 29-yard gain.

Unlike Tech's previous opponents, the Monarchs recognized that Jackson is still a little uncomfortable working down to his second read. As the game progressed, Old Dominion started to show man coverage and then sink that edge player under the slant route. On this play, the design calls for the slot receiver, Sean Savoy, to show a screen to draw Carter forward. This version has no motion to help identify if the Monarchs are in zone or man to man.

Carter almost baits Jackson into an interception. He takes a step forward to Savoy and then begins to sink back to defend against Henri Murphy's skinny post route. Fortunately for Jackson, Murphy's route bends sharper to the inside than Carter's backpedal angle. This allows Murphy to clear Carter just enough for Jackson to have a window to fit his throw. Jackson fires a laser beam right into the opening. It is a beautiful completion. However, I bet offensive coordinator Brad Cornelsen would, in a moment of levity, indicate that he would hope his freshman would check down to Savoy or run with the ball against that coverage.

Just a couple of plays later, Jackson's hubris backfires. The Hokies run a play-action look with Savoy sinking to the flat and Murphy running a much flatter slant route due to the presence of a deep safety.

Carter is reading Jackson all the way. He steps forward, and then with eyes on Jackson, Carter sinks right under the slant. Jackson was too focused on Murphy's route and didn't wait for Carter to commit to Savoy. He forced the ball into double coverage instead of checking down. The result, Jackson's first interception as a Hokie.

"I think maybe he assumed a little too much on the play," Justin Fuente said on Monday regarding Jackson's pick. "We've done that deal several times and I think he assumed how the player was gonna buzz and he didn't buzz and was right underneath it."

While Jackson struggled at moments, especially early against a variety of blitz pressures, he demonstrated that he gets accustomed to the defense and makes good adjustments. As the game progressed, Old Dominion started to present less variety in their coverage. Jackson was able to hit the post off the post-flat combination a couple of other times. However, when Old Dominion tried to sink its safety against the post by Eric Kumah, Jackson checked down to McClease.

Kumah's post route drew three defenders. McClease had all kinds of room to get momentum up the field. Sometimes the right little play can produce a big gain.

Most encouraging is that when Jackson is at his best, you can see him actively monitoring the field. Two plays particularly stood out to me. The first was on the Hokies' opening offensive drive of the game. Jackson faced a third-and-7 and some serious pressure off a four-man blitz by the Monarchs.

Old Dominion is in a dime look. Nickel Denzel Williams (No. 25) feigns an early blitz from the boundary, but drops into coverage while a late blitzer comes from the field-side. To make matters worse, Yosh Nijman oversets against speedy defensive end Tim Ward (No. 2). Ward swims over Nijman to the inside and Jackson knows he is going to take a hard shot.

Phillips gets mugged as he runs the slant. Jackson really wants to go to Phillips. Even as he starts to move to his second progression, you can see Jackson hesitate just a bit. Finally, Jackson goes to his second read. Sean Savoy runs a stick route against OLB Jordan Young (No. 32). Savoy doesn't stop. When he feels tight coverage he moves to give Jackson a throwing lane. Jackson waits until Phillips clears and fires the ball into Savoy. Jackson gets rid of the ball accurately right as his pocket crumbles. This is beautiful third down execution by two freshman in a tough spot. We didn't see this enough in the first three games.

Jackson also moved to his second progression on his third down touchdown pass of the afternoon. Jackson's first read is Phillips on a fade to the boundary. Old Dominion stops that dead when nickel Denzel Williams (No. 25) bails out and doubles Phillips over the top.

Instead of forcing the ball to the primary read, Jackson works back to the space vacated by Williams. C.J. Carroll fakes going to the flat on a rub route and then bends back to the post behind MLB Marvin Branch (No. 37). Jackson works back to Carroll quickly enough to thread the ball in before Carroll runs out of room in the back of the endzone.

Clemson defensive coordinator Brent Venables is one of the best defensive coordinators in the country. His defensive line features elite defensive tackles in Dexter Lawrence and Christian Watkins along with bull rusher Clelin Ferrell. On top of recruiting exceptional talent, Venables loves to use designed zone blitzes to generate pressure and force quarterbacks into turnovers. He can get pressure with four and then bring blitzers from all angles.

Last season, the Hokies neutralized Clemson's defense with misdirection and attacking Clemson's safeties and nickel corners with Cam Phillips. To beat the Tigers this season, Josh Jackson will have to be more efficient and keep drives alive on critical third downs against a variety of zone blitzes. While Old Dominion certainly doesn't present the same kind of test as the defending national champions, the Monarchs' defense gave Jackson a good preview going into the biggest game in Lane Stadium since 2011.