Virginia running back Kevin Parks celebrates with fans on the field after a 24-21 win over No. 12 Georgia Tech. (Steve Helber/AP)

Georgia Tech’s vaunted triple-option offense relies heavily on deception. A dive looks like a dive until it’s an option pitch that turns into a long run. A quarterback’s three-step drop transforms into a draw play that converts a third or fourth down into a first and 10.

To combat this, Virginia’s coaches had a simple message for their players as they prepared to face the Yellow Jackets: Believe what you see.

So the Cavaliers’ defenders stayed true to their assignments, not their instincts, and a team that needed overtime two weeks ago to beat lowly Idaho took down No. 12 Georgia Tech, 24-21, on Saturday at Scott Stadium.

“This is one of those wins against a good team with a lot of accomplishments that you can try to turn the corner on how you think about yourself and how people view your program,” Coach Mike London said. “There’s a long season left to play, but it’s a great start to the second half of the season.”

Indeed, with an upset victory over one of the ACC’s three nationally ranked teams,the Cavaliers (4-2, 1-1) breathed life into a 2011 campaign previously wrought with question marks.

For instance, Virginia’s defense had shown improvement from last season, but exactly how much progress had been made? A season after allowing the Yellow Jackets to gain 536 yards in a 33-21 road loss, Virginia held Georgia Tech (6-1, 3-1) to a season-low 296 yards Saturday.

The Cavaliers used their bye week to pick up on some of the Yellow Jackets’ offensive tendencies and study the blueprint utilized by Georgia Tech’s previous foes. Virginia aimed to limit Georgia Tech’s running backs and make quarterback Tevin Washington prevail with his feet.

Washington tallied 115 rushing yards and two touchdowns Saturday. None of Georgia Tech’s other backs gained more than 37 yards. The Yellow Jackets had 272 rushing yards, which was 88 yards fewer than their season average.

The Cavaliers triumphed in large part because of several critical fourth-quarter stops. Trailing by three with less than seven minutes to play, Georgia Tech faced third and 14 at its 38-yard line. At the snap, Washington dropped back to pass.

Earlier, Washington had converted on fourth and five when he dropped back into the pocket and had the Virginia defense thinking pass. Instead, Washington darted up the middle for a 23-yard gain. He scored a touchdown three plays later.

But when Washington dropped back on the third-and-long play midway through the fourth quarter, several Cavaliers recalled something they had picked up during film study. When Georgia Tech lines up with three wide receivers and one tailback, and that tailback doesn’t immediately leave the backfield, the Yellow Jackets run a quarterback draw.

Junior linebacker Steve Greer saw the tailback stay put and didn’t play the pass as he’d done earlier. Instead, he kept an eye on Washington, and when the quarterback tried to scramble, Greer stopped him for just a two-yard gain.

“We’ve always said as a team that it’s scary how good we can be if we just play well and execute,” said Greer, who tallied a team-high 10 tackles. “And we kind of knew that we could play at a high level. We just had to go out and execute, and we did that today.”

While Virginia did not score in the second half, the Cavaliers executed their offensive game plan, as well. Virginia attempted a season-low 19 passes but was bolstered by a rushing attack that gained 272 yards.

Junior tailback Perry Jones — who recorded a career-high 149 yards — said the offense prepared thoroughly for Georgia Tech’s 3-4 defensive scheme, in which the Yellow Jackets’ front line initially engages the opposing offensive line before backing off to read a play’s direction.

So Virginia’s tailbacks knew the creases through which they had to run would be small. They stayed true to their preparation and ran through those creases anyway.

“What we asked them to do was believe what you see, and if there’s a crease there, stick it in there and hit it hard,” offensive coordinator Bill Lazor said. “If it looks like [the offensive linemen] blocked four yards, add to the run. Make it a six-yard run. If it looks like they blocked three, make it a five-yard run. And sometimes, you’re going to pop through.”