The NFL motto has been around for decades: Defense wins championships. Coming off the league's greatest scoring season since 1965, the Pittsburgh Steelers will be trying to prove that axiom is still valid.
Pittsburgh has been the home of great defenses for more than three decades. The Steel Curtain enjoyed the glitter of four Super Bowl rings. Bill Cowher, standing on the sideline with his tight jaw and aggressive 3-4 style, won 149 games and 12 playoff games in 15 seasons. Enter Mike Tomlin, who created an environment for the defense to grow even more under the direction of defensive coordinator Dick LeBeau.
The Steelers have a chance to write another page in history during Super Bowl XLIII. This is arguably the best Pittsburgh defense since the 1970s. It finished first overall: first against the pass, second against the run. The 3.9 yards per play allowed by the defense was the lowest tally since 1979.
"Without a doubt, this is the best defense that I've ever played on, but we'll see what happens in the next game," safety Troy Polamalu said. "I think that's going to solidify how good we are. This team had to rely more on defense. We had to make a lot more big plays. We caused and forced a lot more turnovers than in the past."
Three years ago, Cowher won Super Bowl XL with great defense and a strong running attack that took pressure off the defense. Quarterback Ben Roethlisberger was only 23 at the time, and the Steelers didn't ask him to throw more than 22 or 23 passes a game. Pittsburgh played a moderately easy schedule, going 11-5 against opponents with a .492 winning percentage, and made the playoffs as a wild-card team.
On defense, the 2005 Steelers allowed 16.1 points a game, third-best in the league. They were fourth in yards allowed and third against the run -- very good, but not great. Nose tackle Casey Hampton, linebacker Joey Porter and Polamalu were the Pro Bowlers. The secondary was in a four-year transition, having moved on from Dewayne Washington and Chad Scott.
Safety Ryan Clark labels the team chemistry as a brotherhood. The Steelers try to play like a band of brothers who are out to help each other.
"We always say, 'Play for your brother,'" Clark said. "We have great guys who are selfless guys. When a guy around here makes a mistake, he feels terrible. We play for each other. That's what makes us a decent team."
In many ways, the success of winning Super Bowl XL makes the Pittsburgh defense even stronger. A decent core group remains in the front seven and in the secondary. Starters Hampton, Aaron Smith, James Farrior, Larry Foote, Polamalu, Deshea Townsend and Ike Taylor remain from the 2005 defense, but this year's version is so much more talented.
Taylor has developed into a Pro Bowl alternate at cornerback. McFadden has developed into a top-flight cornerback and has allowed the shorter Townsend to move into the slot in passing situations. Clark is the perfect safety mate for Polamalu, who roams the field and makes big plays. The development of LaMarr Woodley as a pass-rushing counter to James Harrison provides the pressure that forces quarterbacks into more mistakes.
The NFL tailors the game to offense. Holding penalties are down, so it's harder for pass-rushers to get to the quarterback. That extra half-second opens the door for more spread offenses to operate and move the chains with short completions. The game has changed to a point that the past two Super Bowl winners -- the Colts and Giants -- didn't rank among the top 10 defenses in points allowed. From 1983 through 2005, the Super Bowl winner ranked in the top 10 in that category.
That's the interesting part of Super Bowl XLIII. The Steelers have a defense that can rank among the best statistically in the history of the game. Pittsburgh is old-school. Arizona comes in with a Kurt Warner-led offense that can put up 30 points on any defense.
Which style will prevail?
Historically, the edge should go to the Steelers because the defense is so good, and it has been that way all season. "Everybody talks about our numbers and the 1985 Chicago Bears," Townsend said. "You can look at the numbers, but everyone knows it's about victories. I would say numberwise, we are better than the 2005 team, but the key is that the chemistry is there."
The pass rush and the secondary set this Steelers defense apart from the rest. Monte Kiffin was known for putting up stifling numbers against opposing quarterbacks with his Cover 2 defense in Tampa Bay when Warren Sapp, Derrick Brooks and Ronde Barber were all together. Pittsburgh might be the most productive pass defense since then.
The Steelers allow opponents to complete only 56.5 percent of their passes and hold them to an average of just 5.37 yards an attempt. The quarterback rating against them is a sick 63.4. They grabbed 20 interceptions and forced nine lost fumbles. The tandem of Harrison and Woodley has combined for 27.5 sacks.
What's even more impressive is how the defense held up against what started out as the league's toughest schedule. The Steelers played 11 games against teams with .500 records or better. They won seven. They allowed 80.3 rushing yards per game, Pittsburgh's second-best mark since the merger. The 2,511 passing yards allowed is their third-best total in a 16-game schedule. Including the playoffs, the Steelers' defense has had only one game in which an opposing offense put up more than 300 yards.
In a league that has been pushing the numbers to the offensive side of the ball, the Steelers are trying to swing it back to defense, and they are doing it with perhaps their best defense in more than two decades.
John Clayton, a recipient of the Pro Football Hall of Fame's McCann Award for distinguished reporting, is a senior writer for ESPN.com.