If the adage is true -- that defense does indeed win championships -- then how do the Patriots and Chargers compare leading into Sunday's AFC divisional playoff game?
On the surface, there is the hard-to-miss similarity that both teams play out of a 3-4 alignment. Yet within that comes several differences, according to two NFL offensive coordinators who faced both teams in 2006.
For the Chargers, the discussion unquestionably starts with All-Pro outside linebacker Shawne Merriman, who led the NFL with 17 sacks despite playing in just 12 games (he served a four-game suspension for using steroids).
"The first thing as an offensive coach, when you're facing the Chargers, is trying to come up with an answer for Merriman," said Cincinnati Bengals offensive coordinator Bob Bratkowski, whose unit had success against the Chargers in a 49-41 loss Nov. 12, although Merriman wasn't in the lineup that day.
"He can be an extremely disruptive player, and that's the first thing you see when you watch them. He can change the complexion of a game through both his pass-rush and run-game ability."
Certainly, one of the tradeoffs in paying too much attention to Merriman, who is now in his second season, is leaving an offense vulnerable in other areas, such as the passing game.
"Any time you have to change a little bit of your protection scheme, or you start to have to chip or double, or put a tight end over there, it does alter your route combinations," Bratkowski said. "The key is having everything coordinated, the pieces together, so you can still function offensively."
The 6-foot-4-inch, 272-pound Merriman, who most often lines up over the left tackle on early downs and will move at times in passing situations, has been an infectious presence among the other 10 players on the field.
"They play with tremendous energy, they're fast as heck, and the catalyst is Merriman -- they feed off his energy," said Arizona Cardinals offensive coordinator Mike Kruczek. "Everything starts with [No.] 56 and trickles to everyone else.
"A lot of times, you have to direct your protections toward him, and you have to get the ball out of your hands quickly, because if you hold it for a length of time, he'll find a way to get back there. You can try to chip him with a running back on his way out on a route, or keep a tight end to his side and double with him.
"But there are only so many things you can do, and once you do it, they make an adjustment and it becomes a chess match."
Kruczek, the former Boston College quarterback, apparently found some chinks in the Chargers' armor, because in the season finale, the Cardinals limited Merriman to one sack and rang up 444 net yards of total offense in a 27-20 loss. The Chargers were playing for the top seed in the AFC and weren't holding much back.
If Merriman is the most dangerous player on the Chargers' defense, not to be overlooked is the team's nose tackle, fellow All-Pro Jamal Williams. At 6-3, 348 pounds, Williams controls the middle of the field much like Vince Wilfork does for the Patriots. He's helped the Chargers limit opponents to 100.8 rushing yards per game, the seventh-best mark in the NFL.
"He's a guy who goes snap to whistle, full speed, all out, all the time," Kruczek said. "You see why he's All-Pro, a big guy who is impressive in what he does, how he moves. The thing with him is that if he can get push inside, and Merriman gets off the edge, there is nowhere to go for the quarterback."
How the Patriots handle that pressure figures to be one of the keys to the game, as the Chargers have totaled 61 sacks, ranking them second in the NFL in sacks per pass attempt. Merriman (17), outside linebacker Shaun Phillips (11 1/2), and defensive Luis Castillo (7) rank 1-2-3 on the team in sacks.
Kruczek said the Chargers have been effective at times with zone blitzes, utilizing a scheme in which a defensive lineman will drop into coverage and the other side of the field will be overloaded with rushers, putting stress on the offensive line.
"They hide it pretty well and sometimes you don't have the time to find it," Kruczek said.
The flip side of such pressure, however, is that the opportunity could be there for a big play for the offense.
"If Tom Brady sees that, a defense could be in trouble," Kruczek said. "He's an extremely intelligent quarterback."
While the Chargers' 3-4 defense under coordinator Wade Phillips can be pressure-based, as evidenced by their 61 sacks, the Patriots' 3-4 set takes on a different personality (29 sacks). Bratkowski believes three keys to the Patriots' defensive success are taking away an offense's signature, using an ever-changing approach, and consistently disguising their intentions.
"The Patriots do a great job of preparing for the things you like to do, anticipating what your bread and butter is, and preparing themselves to try to stop it and take advantage of it," he said. "They'll show you a look you think you've seen before, and it ends up being something different. The biggest challenge with the Patriots comes on game day, with you making the adjustment on how they plan to stop you. It's usually different than they played a week before."
Because of this, Bratkowski believes any offense preparing to face the Patriots must be willing to adapt after the opening kickoff.
"From a preparation standpoint, what you have to do is go on what you see from them most of the time, fine-tune the things you do, then have your players aware that you'll have to make adjustments on what their plan is for that particular game, and go about your business as normal from there," he said.
Bratkowski's high-powered Bengals attack was held to a season-low point total by the Patriots in a 38-13 loss Oct. 1.
When he thinks back to that day -- and preparing for a banged-up New England defense that was without starting cornerback Ellis Hobbs and starting safety Eugene Wilson, and was utilizing receiver Troy Brown as a defensive back -- Bratkowski remembers being impressed.
"The thing that amazes me about New England is the ability to overcome injuries, and still play good, quality football," he said. "That's a credit of the coaching to the backup players."
Kruczek, who traveled to Foxborough for a 2006 preseason game against the Patriots, added that the New England defense has "a veteran group of guys and leaders in critical areas," and expects to see a few unexpected wrinkles from the unit Sunday.
"You always keep a couple of bullets in your chamber, just in case you're in a situation like this," he said.
Added Bratkowski, "They're both elite teams in the league, both very well-coached, and both have really good players. If New England can make Philip Rivers have to beat them by throwing it, which probably means they got ahead early, that would be to their advantage. If San Diego can run the ball, and stay in the lead while letting Philip Rivers manage the offense, that will be to their advantage."