LAKE FOREST, Ill. -- Far too often last year the Chicago Bears defense got burned in deep coverage.

Over the course of the 2011 regular season, the Bears gave up 20 pass plays of 30-plus yards and nine pass plays of 40-plus yards, including a pair of 70-plus yard touchdown bombs to New Orleans' Devery Henderson and Detroit's Calvin Johnson.

But it's been a different story so far this season.

There have been only two completions of 30 or more yards against the Bears defense over the first six games (Jacksonville's Cecil Shorts, 34 yards and St. Louis' Danny Amendola, 30 yards) and neither were harmful in the grand scheme of things.

Why the turnaround?

Bears cornerback Charles Tillman credits the improved play of safeties Chris Conte and Major Wright and the work of the coaching staff for all but eliminating the busted coverages that previously plagued the defense.

"Just talking from a safety standpoint, Major Wright and Chris Conte have done a phenomenal job of not giving up the big plays and letting guys get behind them like they did last year," Tillman said. "A lot of that credit goes to (safeties) coach (Gill) Byrd, he's done a great job of coaching those two guys and they've done a great job of receiving the coaching. So I tip my hat to all three of them."

The ultimate litmus test for the secondary will be when the Bears face Carolina Panthers receiver Steve Smith on Sunday. Smith got behind the Bears defense last year for a 53-yard gain, the latest in a long line of downfield plays he's made against the Bears in his career.

But the secondary can't do it alone.

It would be a mistake to overlook the role the Bears defensive line has played in limiting opponents in the deep passing game. A defensive back’s best friend is a pass rush, and the Bears’ talented and deep defensive line has provided ample pressure in the early parts of the season.

In an ideal world, the Bears generate their pressure from the front four which allows the other seven members of the defense to drop back into coverage. That plan has worked nearly to perfection. The Bears are currently tied for No. 1 in the league with 17 sacks and fourth in yards per pass play (6.2) when they send four rushers, according to ESPN Stats & Information. Additionally, 11 of the team's 21 interceptions have occurred when the Bears have exclusively sent pressure with the front four.

"I don't think teams have tested us deep a whole lot," Conte said. "But I think teams will. That just shows that our defensive line is getting after the quarterback and not giving him enough time to really get those throws down the field. I would say the pass rush is the biggest reason for all that."