INDIANAPOLIS -- For 16 seasons, defenses have wondered how Peyton Manning completed throws with the receiver blanketed by a defender.
"It's a matter of inches against him," Colts safety Mike Adams said of Manning, whose Denver Broncos will host Indianapolis in a divisional playoff game at 4:40 p.m. ET Sunday. "Against the Broncos, you can't make mistakes. We have to play a perfect game."
Adams spent the 2012-13 seasons in Denver as Manning's teammate. "Being there, I noticed that every time a team made a mistake, he made them pay."
Adams saw Manning's intensity in practice, his dislike when the special-teams unit was on the field because it meant he wasn't taking snaps and working on his timing with his receivers, his anger on the sideline after he made a mistake, despite the defense telling him not to worry about it because they'd "get the ball back." That wasn't acceptable to Manning.
"He's that guy; he wants every snap," Adams said. "One thing I learned about the great Hall of Famers and players is that they all talk about loving to practice. He really does. It carries over."
It's up to the Colts to get Manning frustrated and angry if they expect to have any chance of advancing to the AFC Championship Game for the first time since the 2009 season, when Manning was their quarterback.
The goal of any defense facing Manning is disguising coverages.
"If you recognize something [as a defense], you can't yell it out," Colts linebacker D'Qwell Jackson said. "You have to have some kind of nonverbal communication between the guys that need to know, because if he picks up on it, he's going to change it. He watches body language and listens to what is going on."
The slightest misstep -- showing blitz too soon or dropping too deep into coverage -- and Manning will recognize it. Think run, and Manning checks to a play-action pass. Think pass, and Manning hands the ball off to C.J. Anderson. Being close to perfect often isn't good enough against him.
"One time in practice, me and Champ Bailey was on one side and I had great coverage on Eric Decker. [Manning] saw me move forward and he threw the ball, perfect, right over my head," Adams said. "One bad step. Me and Champ looked at each other wondering how he made that throw. I remember that because right after that play, I asked why he threw that ball. He said, 'I saw you move forward and once you did that, I knew you couldn't recover.' "
And the Colts haven't recovered when facing pocket-passing quarterbacks this season. Manning, Ben Roethlisberger, Tom Brady and Tony Romo went a combined 99-of-135 for 1,266 yards, 15 touchdowns and only two interceptions against the Colts. And Indianapolis was 0-4 in those games.
The Colts finished with 42 sacks, the majority of them coming on blitzes because they didn't have pass-rush specialist Robert Mathis all season. It shouldn't be surprising the Colts only sacked Manning, Roethlisberger, Brady and Romo only twice, because good quarterbacks know how to beat blitzing teams.
"You've got to do a great job of mixing things up," Colts coach Chuck Pagano said. "There's nothing that [Manning] has not seen. Obviously, we know he's going to do his homework and be prepared as well as any quarterback can be prepared. We just got to do a great job of mixing things up."
Manning was sacked just 17 times this season, the fewest among full-time starters. Just think about the coyote chasing the roadrunner: You think you've got Manning, and he sidesteps the defender or gets rid of the ball right before getting hit.
"He knows exactly where he wants to go before the ball's hiked," Colts defensive lineman Cory Redding said. "[He's] looking at the safeties, finding that tail, seeing where you want to go with the ball, delivering the ball in a window where only his receivers can get it. His delivery, his movement in the pocket, his awareness -- all those things he's been very successful for all these years. He's still got it."
Manning's stats the second half of the season provide some hope for Indianapolis. He threw for 64 fewer yards per game, his completion percentage dropped 4 percent and he threw 19 fewer touchdown passes than the first nine games.
The Colts, however, aren't buying the notion that Manning, who will turn 39 in March, isn't as effective anymore.
"Peyton is still Peyton," Adams said. "Hearing rumors about him not being the same because he's not throwing for 300 yards or whatever -- Peyton is Peyton. They're winning games ... and that's all that matters."
A key, according to the Colts, is to try to force Manning outside the pocket. But many teams have tried and failed.
"You get to the point in the season where you're going to run into the elite-style quarterbacks the more you win," Jackson said. "So we're fully aware of it. We know the challenge ahead and they've also got to prepare for us as well."