"Prior to this season, the prevailing thought was that the Pittsburgh Steelers were the mountain that Joe Flacco had yet to conquer.

That has obviously changed after the quarterback led the Ravens to their first regular-season sweep of the Steelers since 2006. But maybe the focus should have been on a different AFC North rival.

In six career meetings against the Cincinnati Bengals — the Ravens' opponent this Sunday — Flacco has endured some of the poorest outings in his career. Perhaps not coincidentally, the Ravens are 1-3 in their last four contests with the Bengals.

"They are a physical football team," Flacco acknowledged. "Like I said, they have played well. Their offensive line, their defensive line, they are two pretty good groups. They'll fight 60 minutes, and they fight to the whistle hard on each play."

One factor in Flacco's struggles against Cincinnati has been the defense's use of the cover-2.

In this scheme, the cornerbacks run with the receivers, but hand them off to two safeties, who split the field and have deep coverage responsibilities. In a 4-3 defensive front like the one the Bengals play, the middle linebacker drops back into coverage to shadow a tight end or a receiver running an underneath route."