Eli Apple knows that any great pass defense is like a tree: He and other Ohio State defensive backs are the branches, but the front four is the root of it all.

Eli Apple knows that any great pass defense is like a tree: He and other Ohio State defensive backs are the branches, but the front four is the root of it all.

"Anytime you get a team in passing situations and you let our front four go out and eat, you can kind of feel the quarterback wanting to take faster throws," Apple said. "We know that we can just sit on routes and be a little bit more aggressive knowing the ball's gonna come out fast."

>> Follow Rob Oller on Twitter during the games, become a part ofScarlet & Gray MatterinThe Dispatch

Such symmetry has been there thus far as the top-ranked Buckeyes head into Saturday's matchup with pass-heavy Western Michigan at Ohio Stadium. The Buckeyes rank fourth nationally in pass defense efficiency and fifth in fewest passing yards allowed (119.0 average) - both a far cry from the days in 2013 when duck for cover was the credo when an opponent came to pass.

"We went from one of the worst pass defenses in America two years ago - I know we're No. 1 in the Big Ten" now, coach Urban Meyer said. "Playing at a high, high level - that's obviously correlated with the pressure we put on the quarterback."

All-America defensive end Joey Bosa, tackle Adolphus Washington and as many as seven others rotating into the group have set the tone up front. But the secondary - safeties Vonn Bell and Tyvis Powell roaming the middle of the field and cornerbacks Apple and Gareon Conley playing press coverage - is performing at an elite level, too, Meyer said.

>> Get the most out of college football season, follow @BuckeyeXtra on Twitter

All four starters in the secondary have an interception this season, and Bell had a scoop and score of a fumble two weeks ago against Hawaii.

"I haven't watched all the secondaries in the country, but I take ours," Meyer said, "especially with the way they're playing, the way they work, the way they're coached."

Such aggression and playmaking is what Meyer envisioned when he brought in Chris Ash last year to make over the scheme, in conjunction with fellow co-coordinator Luke Fickell. Ash indicated the change is as much a mindset as it is schematic.

"We talk about some of our objectives for each game - every day, really," Ash said. "One is to believe in what we're doing and believe in themselves.

"We want to go on the field and challenge everything. We're doing that right now at the corner position, safety position, linebacker position. We're challenging throws. We want to produce takeaways, and we're doing that. In the first three games, we've been able to do that as a defense, not just in the secondary."

Ash explained that much of the secondary's success begins when linebackers Joshua Perry and Darron Lee "reroute" receivers - knocking them off their intended patterns - and when the line gets pressure on the quarterback.

>> Click here for details on how to win tickets and trips to Ohio State's football games fromDispatchReader Rewards

Confident play by those in the secondary only has enhanced the performance. It has come about in an almost 24/7 approach to the game as a group, according to Apple.

"We're very close. We're always hanging around together. There's great communication going on between us," Apple said.

"That's the biggest thing, when you're always communicating, always hanging out with each other, you get a good feel for each other's personalities and strengths, you're naturally going to do well."