The Bears' incredible 20-point comeback in Week 6 against the Cardinals changed more than just the fortunes of Dennis Green and the Cardinals.
Matt Leinart seemed to be picking apart the Bears' Cover 2 defense. Cover 2 couldn't cover much. Rex Grossman was making mistakes, and the Bears' offense was scoreless in the first half. The Cardinals led, 20-0, and the Bears needed a change.
Defensive coordinator Ron Rivera made a halftime switch that further showed he's ready for a head coaching job. He made the first significant adjustment to the Bears' Cover 2 scheme. Pressured to come from behind, Rivera ordered more man-to-man coverages and more one-deep coverages.
It's a change that stayed with the team. The Bears aren't sitting back in zones as much, and those changes in the secondary will play a big role in Super Bowl XLI.
"We learned in the Arizona game, we can get up in a defense and challenge a team," Rivera said. "We came up and played more bump-and-run. Before, we were a heavy Cover 2 team, but in that game, we were sitting back a little too much and letting them throw the ball short. We played a little 4-6 and we let those guys get a little more physical."
The Bears came back with two defensive scores and one special teams score to beat the Cardinals, 24-23, and the Bears' Cover 2 started to evolve in a different direction.
"In my eyes in that game, our guys showed we can get up in that type of defense and challenge," Rivera said.
Man-to-man coverage can be an island for cornerbacks. For starting cornerbacks Charles Tillman and Nathan Vasher, they feel as though they are on Fantasy Island. Cover 2 is still the Bears' base defense, but the switch to more man gives them more of a chance to make big plays against the Colts in the Super Bowl.
Part of the change was out of necessity. The early-season loss of safety Mike Brown was bigger than the team let on. Not only was he a leader in the secondary, he was an important part of the Cover 2. Without him, the Bears weren't the same defense.
"We're going to man-up, we're going to press and I think we have the corners and the secondary to match up on wide receivers and tight ends," Vasher said.
"It's something that Coach [Lovie] Smith and Coach Rivera wanted to do," Tillman said. "It's not really our call. I don't make calls. I just play. I wouldn't mind playing man all the time. I have confidence in myself and in Nathan that we can play it. That's what we do. We are corners. We're supposed to cover guys whether it's man or whether it's zone."
What strategy Rivera comes up with will play a big role in determining the outcome of Super Bowl XLI. If Tillman doesn't get help on Harrison, Peyton Manning will try to exploit Tillman and get the ball to Harrison.
Harrison is a master of precise routes, double and triple moves, and accelerating coming out of breaks. Those skills could give Tillman trouble. But Tillman has his own weapons. He's strong and could stop Harrison at the line of scrimmage with aggressive bump-and-run coverage.
"The Bears' secondary plays extremely well together," Harrison said. "From my perspective, I want to go out and play the same way we've been playing all year long. I'm not going to go out and change what I've done all year long. We're going to go out and call our plays and do the same things we've done all year."
Along with figuring out how much man and zone to use, Rivera faces another tough decision. The Colts often line up tight end Dallas Clark in the slot, which forces him to decide whether to use a cornerback or a linebacker to cover him.
If the Bears stay in their regular defense, that means less time on the field for cornerback Ricky Manning Jr. Manning has been an important part of the secondary. He's the third cornerback and he's a good one. Though he's not one of the biggest corners in the league, he's one of the toughest and doesn't mind matching up against a tight end.
But if the Bears stay regular, linebacker Lance Briggs probably gets Clark.
"You can't be afraid to play your regular defense against him," Rivera said. "I think what [the Colts] do very well with Dallas is that they move him around and use his ability as a receiver. When you start to see a lot of trouble is when you start going nickel exclusively, then they just tighten him down and run the football. Now, you're asking a defensive back to come down and be part of your run defense, which plays into their advantage."
Decisions. Decisions. Decisions. Rivera has some tough ones, but he made a tough one in Week 6 that paid big dividends.
John Clayton is a senior writer for ESPN.com.