The rise of Duke football, which hit a tipping point with a 10-win season in 2013, has always fallen on the shoulders of David Cutcliffe. A quarterback guru and one of the top offensive minds in college football over the past two decades, the 61-year-old head coach afforded the program the patience it desperately needed, building from three- and four-win seasons to three consecutive bowl appearances.

Given Cutcliffe's background -- most notably working with the Manning brothers at Tennessee and Ole Miss -- this exponential improvement in the program's national status was credited to an improved offense.

The Blue Devils developed productive quarterbacks in Sean Renfree and Anthony Boone, found playmakers like wideout Jamison Crowder and even placed an offensive lineman, Laken Tomlinson, in the NFL Draft for the first time since 2004. The 2012 and 2013 teams both averaged more than 30 points per game, culminating in a 52-48 barnburner against Texas A&M in the 2013 Chick-fil-A Bowl, and that was the general expectation moving forward.

That identity has shifted over the past two years. Defensive coordinator Jim Knowles and his staff have quietly put their stamp on the Blue Devils' success. In some ways, it's been a defense-reliant program since that showdown with the Aggies in Atlanta. Duke's defense bested its offense in the national rankings in both scoring and efficiency last season, and that gap has only widened following key departures on the offensive side of the ball.

In short, Duke's defense, led by preseason All-American safety Jeremy Cash, is carrying Cutcliffe's team to the top of the Coastal Division.

In four games against FBS competition, Duke (4-1, 2-0 ACC) has given up a total of 52 points. That's ignoring a 55-0 shutout of North Carolina Central, too. After holding offensively challenged Boston College to just seven points in Week 5, the Blue Devils find themselves in impressive company, holding opponents to 10.4 points per game.

Knowles' unit has certainly not faced a top-tier offense -- in fact, Duke has squared off against three teams ranked 100th or worse in offensive efficiency; Georgia Tech's hit-or-miss option is its biggest test to date -- but even opponent-adjusted statistics tabbed the Blue Devils as a top-10 unit before they manhandled Boston College.

So what's going right for Cash & Co.? Well, they found defensive balance with their upperclassmen-heavy unit. The Blue Devils are particularly stingy against the pass, holding the Eagles to just 141 yards through the air on Saturday. They are one of the least-penalized groups nationally. They pressure passers and swarm to the ball. Perhaps more than anything, this group has learned how to get off the field. Here's a five-year snapshot of Duke's defense on third downs (opponents' conversion rate, national ranking entering Saturday):

2011: 43.0 percent (87th)

2012: 41.8 percent (77th)

2013: 37.3 percent (45th)

2014: 34.4 percent (17th)

2015: 22.9 percent (5th)

Duke needs its defense more than ever if it's going to challenge for a spot in Charlotte for the ACC Championship. The Boston College matchup was destined to be a low-scoring struggle, but a 9-7 win doesn't exactly instill confidence in Cutcliffe's retooled offense. As long as Duke can keep limiting mistakes and getting off the field at every possible opportunity, though, the schedule should provide enough breaks to ride this unit to another successful season.

This remains a program molded in David Cutcliffe's image. He spent years laying this foundation, but the Blue Devils are finding ways to do what good programs do: Adapt. The defense is clearly ahead of the offense in 2015.

Duke hasn't let that disrupt the best run in program history. Not yet.