INDIANAPOLIS — Bengals coach Marvin Lewis understands what it takes to build a stingy defense.
The right scheme, the right players and the right mindset. So when Lewis put in the tape of Indianapolis this week, he was impressed.
"I think they've morphed," he said. "(Defensive coordinator) Greg (Manusky) has them doing some different things on defense and that has really stepped up with the loss of (Robert) Mathis. I think guys are really doing a great job."
Hey, it's a start for a unit that has spent most of the past decade being overshadowed by Peyton Manning, Andrew Luck and the Colts' high-scoring offense.
On Sunday, Cincinnati faces the daunting challenge of poking holes in one of the league's most improved groups.
Sure, the Colts lead the league in yards per game (444.0), points per game (31.5) and possession time (36:28). But now they also have the best defensive third down conversion rate in the NFL (29.7 percent), are No. 6 in sacks (17) and on the cusp of cracking the top 10 in both run and pass defense.
And they've been downright dominant during this four-game winning streak with 16 sacks and eight turnovers while allowing just 18.8 points per game.
The Colts (4-2) have done it despite losing Mathis with a season-ending torn left Achilles tendon, defensive tackle Arthur Jones with an ankle injury and free safety LaRon Landry who has missed the past two games as part of a four-game suspension.
Lewis wasn't the only one who's noticed a difference during film sessions.
"I think they're flying around, getting to the ball quickly," Bengals quarterback Andy Dalton said. "They've got a lot of high-motor guys that are kind of nonstop, so that's something that we've got to be prepared for."
Dalton should recognize what the Colts are doing. Lewis, like Colts coach Chuck Pagano, previously served as defensive coordinator of the Ravens and both have similar philosophies.
For most of Lewis' head coaching tenure, the Bengals have generally been ranked among the league's best defenses.
Over the past two games, the Bengals have been gouged for 80 points and 936 yards. They're now ranked 29th against the run, 22nd against the pass and 28th overall.
The Colts don't believe numbers alone tell the whole story.
"Defensively, they've got a bunch of guys up front that can put pressure on the quarterback, athletic guys, linebackers that can run and hit and secondary personnel that can play," Pagano said.
Here are some other things to watch Sunday.
THE HEADLINERS: While the diverging defenses will be a big part of the story, so will two of the NFL's best young quarterbacks. Luck and Dalton both have quarterback ratings topping 98, lead offenses that are ranked in the top five, have a cadre of talented receivers and runners. And neither has missed the playoffs during their pro careers.
SACK ATTACK: Cincinnati's offensive line has done a marvelous job protecting Dalton this season. He's been sacked a league-low two times. The Colts, meanwhile, are keeping pace with last season's sacks total despite losing Mathis, the 2013 league champ. The last time Indy faced a similar scenario, they harassed Baltimore's Joe Flacco. Indy wound up with four sacks and four turnovers in a 20-13 victory. The winner of this interior battle will clearly have the upper hand.
STANDING PAT: Pat McAfee may be the most dangerous special teams player in the league. All he's done since re-signing with the Colts during the offseason is produce the league's best net punting average of 44.8 yards, put 11 of his 21 kicks inside the 20-yard line and produce a league-high 33 touchbacks on kickoffs. He's also changed the game by going 3 for 3 on onside kicks, too.
TRICKY GUY: While the Colts have put opponents on notice that they're not afraid to try onside kicks, the Colts are preparing for Mohamed Sanu's trick plays, too. He is the Bengals top receiver with 27 catches, 354 yards and three TDs. But he also has one carry for 4 yards and has completed both of his pass attempts for 68 yards with one TD.
PLAYOFF PICTURE: Sunday's game could have long-term playoff ramifications. This is the weekend's only game between teams that have sole possession of their division lead, giving the winner the inside track to potential playoff positioning.