METAIRIE, La. (AP) — The ideas Gregg Williams covered in his first formal meeting with the Saints’ defense had nothing to do with formations or coverages and everything to do with nastiness and fear.

‘‘That was a defining moment as far as mindset,’’ Saints linebacker Scott Shanle said, recalling a speech of about 30 minutes that Williams delivered back when offseason workouts began last spring. ‘‘This defense is the type of defense everybody in the NFL would want to play in.’’

The Saints are not immune to giving up big plays and lots of yards. They ranked 25th in the regular season in yards allowed (357.8 per game), yielding more than 400 in a game six times this season.

Such statistics could bode ill with a quarterback like Brett Favre and the Minnesota Vikings visiting New Orleans on Sunday in the NFC championship game. Yet Williams said on Thursday that he doesn’t worry about that.

The Saints’ defense gives up yards because Williams and his players take an aggressive approach that sometimes means taking risks. The reward can be game-changing plays. The Saints were second in the NFL this season in turnovers with 39 on 26 interceptions and 13 fumble recoveries.

‘‘That’s a huge part of our success so far, being able to turn over the ball, being able to score when we do get the turnovers and change the game,’’ defensive end Will Smith said.

The system has been a fantastic fit for veteran free safety Darren Sharper, who called Williams a ‘‘genius’’ as far back as training camp, before his nine regular season interceptions, three of which he returned for scores.

New Orleans also had 35 sacks this season, an improvement of seven over the previous season.

Looking at the big picture, the Saints are not about to complain about Williams’ results. New Orleans went 13-3 during the regular season, setting a franchise record for wins and securing the first No. 1 NFC playoff seed in team history. The Saints then pounded Arizona 45-14 last weekend in a divisional-round playoff game to get within a victory of the club’s first Super Bowl appearance. Their defense forced six punts and two turnovers, sacked Cardinals quarterback Kurt Warner once and did not allow him to throw for a touchdown.

Favre said Williams’ defenses can be tough to decipher because of constant changes in formations, coverages and disguised blitzes.

‘‘It’s kind of a risk-reward type of defense, and you see that it’s made a huge difference for those guys,’’ Favre said.

Williams reflected back to a meeting he had, shortly before he joined the Saints, with head coach Sean Payton.

‘‘His No. 1 thing was, ’I want this defense to play with a swagger. I want it to play the way our offense plays,’ and I said at that point in time, and I said it tongue in cheek, ’Well, you probably found the right guy in that respect.’’’

Williams considers himself a disciple of former longtime defensive coordinator and former Philadelphia head coach Buddy Ryan, under whom Williams worked with the Houston Oilers in the early 1990s.

‘‘Buddy Ryan will tell you this: ’Unless your defense is feared, then it’s not really a legitimate defense,’’’ Williams said. ‘‘And how that comes about is through contact, comes about through speed and it comes about through the fear of making a mistake against that type of defense.

‘‘We don’t believe in cover corners. We think everybody has a facemask and shoulder pads, and you’re supposed to use them. And if you don’t use them, then you turn into a highway cone and stand over by me’’ on the sideline.

Sometimes, Williams can be seen smiling on the sidelines after a Saints defensive player has been flagged for scuffling with an opponent or making a heavy hit on a receiver or quarterback that was deemed by officials to be unnecessarily rough.

‘‘He doesn’t want you to get personal fouls, but he always says he’ll never fault you for making a mistake if you were going 100 miles an hour and your intent was there,’’ Shanle said. ‘‘He just wants you playing wide open … and if you get a penalty, or you miss something and you were going 100 miles per hour, he can live with that.’’

It was an approach that served Williams well after he became defensive coordinator of the Tennessee Titans in the late 90s. He routinely had top 10 defenses, including the NFL’s top-ranked unit in 2000. He also had highly ranked defenses as a head coach in Buffalo and as defensive coordinator in Washington.

Early this season, it appeared he might have another top 10 defense in New Orleans, but as the season wore on, the yards allowed started piling up. The worst games came when key players — such as starting cornerbacks Jabari Greer and Tracy Porter — were out with injuries.

Several Saints defenders said a combination of late-season mental and physical fatigue had a hand in the unit’s declining performance, but the defense was fresh and refocused again for the playoffs.

‘‘You can see points in our season where at times we were playing lights-out defense. Other times we’re giving up the big play, giving up some points,’’ linebacker Jonathan Vilma said. ‘‘We’re playing lights-out defense again.’’