San Diego Chargers wear underdog collar with some comfort

Being labeled the biggest, baddest team on the block doesn’t matter much in the NFL playoffs.

Since realignment in 2002, only twice has a No. 1 seed in either conference gone on to win the Super Bowl: New Orleans in 2009 and New England in 2003. Just as many No. 6 seeds have lifted the Lombardi Trophy during that span: Green Bay in 2010 and Pittsburgh in 2005.

This is especially meaningful to the sixth-seeded San Diego Chargers, who know firsthand that a gaudy regular-season record isn’t all it’s cracked up to be. They open the playoffs as a seven-point underdog Sunday at Cincinnati, where the Bengals have not lost this season.

“There have been years when we’ve sat around here and it’s like, ‘Oooh, the Chargers are the team to beat!’” quarterback Philip Rivers said. “And we didn’t win.”

The Chargers were 14-2 in 2006 … and lost their first playoff game.

They were 13-3 in 2009 … and again were one and done.

San Diego is in the playoffs for the seventh time since getting to its only Super Bowl at the end of the 1994 season. The Chargers are 3-6 in postseason games in those 19 years, with all the playoff victories coming in the 2007 and ’08 seasons.

The ’07 Chargers were 5-5 before winning their final six games and carrying that momentum all the way to the AFC championship game against the Patriots.

The ’08 Chargers slipped all the way to 4-8 before going on a four-game run, sneaking into the playoffs, then beating Indianapolis in the opening round.

So for Rivers and a handful of his teammates who have been in San Diego for a while, there’s some comfortable familiarity with their current situation. They tumbled to 5-7 this season — their last loss a Dec. 1 home defeat to the Bengals — then won their final four games and slipped into the postseason when Baltimore and Miami faltered down the stretch.

“When we lost to Cincinnati here to go 5-7, it was like, ‘All right, boys….’” Rivers said this week during a break from practice. “We weren’t going to shut it down. We’re too prideful to quit. But it was like, ‘If we lose another one, we’re out. We have to win four in a row to even have a chance.’

“So we beat the Giants and it was, ‘We’re alive for another week.’ We beat Denver, and that felt like a playoff game. And the last two truly were, because Miami and Baltimore lost before we kicked it off. So it was, ‘All right, Chargers, you win and you move on to the next round.’ And then last week, same deal.”

Some people believe the pressure is off the Chargers, that whatever they achieve now is icing, considering they teetered on the edge of elimination for weeks and were written off by just about everyone. But Ken Whisenhunt, their offensive coordinator, doesn’t see it that way.

“I don’t buy into that thing where there’s no pressure on you and that you’re playing with house money,” Whisenhunt said. “I think you get into that mentality of, the last four weeks they’ve had to lay everything on the line to get in.… We’ve seemed to play well this year as an underdog, an us-against-the-world type of mentality. Hopefully that will pay off for us in the playoffs.”

The Chargers mustered just one touchdown in a 17-10 home loss to Cincinnati on Dec. 1. In the four games that followed, San Diego scored 37, 27, 26 and 27.

“I think we’ve grown” since losing to the Bengals, Chargers tight end Antonio Gates said. “We’ve matured a lot as a team. One thing is, when you have a new staff, guys coming in and out from different places, you’re adding guys to a team, it takes time to build that continuity.

“You can see the confidence and sense of urgency that we have. You can just see it’s a different team, different situation. You just build confidence in winning.”

That said, the team that wears blue is painfully green. Whereas Cincinnati is in the playoffs for the fourth time since 2009, the Chargers are in the postseason for the first time since 2009 — and their roster is understandably light on experience. They have a rookie head coach and general manager, and 37 of the players on their 53-man roster have no postseason experience.

Predictably, the upbeat Rivers has found a silver lining.

“I think that can be a positive in the sense that it’s not like [grumbling pessimistically], ‘All right, boys, here we go. It’s the playoffs. We’ve got to make sure we do better this time,’” he said. “Well, this group doesn’t have much history together. The fact that it’s like, ‘OK, let’s go. Let’s keep on rolling.’ And the fact that we’ve been in playoff mode for the last month.”

Few quarterbacks have been as scorching as Rivers this season. His 105.5 passer rating is second in the AFC to Peyton Manning’s 115.1, and his touchdowns-to-interceptions ratio is almost 3-to-1 this season (32 touchdowns, 11 interceptions) after struggling with those numbers the previous three seasons (83 touchdowns, 48 interceptions).

Heading into this season, Rivers was annoyed by a question coming from all corners — “Who is going to fix Philip?” — and he’s happy he isn’t hearing it anymore.

“The consistency is what I’m happy about,” he said. “I could find you pockets of games, or strings of games the last few years, where I played as good or better than I’ve played this year. But I’ve just been more consistent.

“But all that goes out the door now. It’s ‘Now what are you going to do?’ When you get to playoff football, it’s a different deal. No one’s going to remember our good December unless we have a heck of a January.”

sam.farmer@latimes.com

Twitter: @LATimesfarmer