With a three-and-out possession and a takeaway that led to a 7-7 tie, the Vikings defense was outstanding through the first 13 minutes of Sunday's game at Cincinnati.

But then things began to unravel when defensive coordinator Alan Williams dialed up a coverage that's been a Vikings staple through good, bad and ugly times since Mike Tomlin arrived as Brad Childress' defensive coordinator in 2006.

With the Bengals facing their first third-and-long situation — third-and-10 from the Vikings 49-yard line — Williams called for the Cover 2 zone. From above, Cover 2 looks like an umbrella, with two deep safeties splitting the field, three underneath defenders dropping left, right and middle, and two corners dropping short left and right.

"The old cliché is it's a rush-and-cover type of scheme," linebacker Chad Greenway said.

"You get back to your spot and read the quarterback. Your rush has to win up front and you have to force the check-down throw in front of you. Then you have to run up and make that tackle before they get the first down."

No team just sits in a Cover 2 scheme for an entire game. But teams that trust the philosophy as much as the Vikings do are said to be "Tampa 2" teams, a tip of the helmet to former Buccaneers coach Tony Dungy, who used the scheme as a way to contain Randy Moss' freakish speed when the Bucs and Vikings were NFC Central Division rivals.

Current critics of the defense make two primary points: 1. It's outdated because quarterbacks are better and more accurate than they were when Dungy made the defense popular more than a decade ago; and 2. Hall of Famers are likely to represent every level of those Tampa Bay defenses. Tackle Warren Sapp was selected this year, outside linebacker Derrick Brooks is expected to be a first-ballot selection in two months, and safety John Lynch could be announced as a finalist next month. Cornerback Ronde Barber is yet another possibility when he becomes eligible.

Bengals quarterback Andy Dalton enjoyed Williams' first Cover 2 call and a few more after that Sunday. On the first one — the third-and-10 — Dalton found a gaping hole and delivered an 18-yard strike to Marvin Jones. Two plays later, the Bengals took a 14-7 lead on a 29-yard pass to A.J. Green.

Pressure gone

The third-down conversion — the first of six on the day that came on third-and-7 or longer — turned a punting situation into a lead the Bengals never relinquished. A review of the play revealed a number of issues that worked in Dalton's favor.

First, the pass rush was nonexistent. In fact, the Vikings actually rushed only two defenders, dropping Kevin Williams 5 yards and left end Brian Robison to his left to cover running back Giovani Bernard.

Second, with no pass rush, Greenway didn't drop far enough, which created a gap behind him. And, third, safety Harrison Smith, whose turf toe injury was bothering him, didn't close fast enough.

"If you play any coverage right, you're going to play well," Smith said. "There's always going to be gaps in every coverage. So as a player, you just got to make plays."

Without a strong four-man pass rush, the Cover 2 scheme is doomed. On Sunday, it was as doomed as doomed can be, especially with a secondary overwhelmed by injuries.

"We haven't been as consistent rushing the passer as we have been in the past," Vikings coach Leslie Frazier said. "And that definitely affects what we try to do systematically, without question. A lot of what we do revolves around being able to rush with four."

Dalton preyed on Cover 2 zones during two other significant third-and-long situations in the first half. First, he threw a 17-yard pass to Green on third-and-11. Then, five plays later, he beat Cover 2 again with a 16-yard touchdown pass to Jermaine Gresham on third-and-10.

Rodgers ruled

At 4-10-1, chances are the Vikings will be making significant changes after the season. One of them could include a different defensive core philosophy for the first time since 2005.

Chances are Packers quarterback Aaron Rodgers won't be happy about it. In his 11 regular-season meetings with the Vikings — all of them since 2008 — Rodgers has posted the highest passer rating (117.9) of any NFL quarterback against one team since 1970. He has completed 71.7 percent of his passes (256 of 357) for 3,125 yards, 26 touchdowns and four interceptions against the Vikings.

Included in Rodgers' 130.6 rating in his one meeting with the Vikings this year was a perfect performance on third and fourth downs. He went 12-for-12 for 187 yards, eight first downs and two touchdowns. He also ran for first downs twice on third down.

Rodgers isn't the only quarterback to have feasted on the Vikings this season. Among the many opponent highlights, Cam Newton (143.4), Russell Wilson (151.4) and Dalton (136.5) each posted career-high passer ratings against the Vikings.

"I've played [Cover 2] so much, so I guess I like it," Greenway said. "Yeah, I obviously know there are a bunch of weaknesses to it, like there are in any defense if the other team knows what you're doing and understands what you're trying to get to, and things don't sync up with the zone [responsibilities]. It can be difficult to win, but it's been good for a while."

Mark Craig • mark.craig@startribune.com