It’s No Shoo-In for 49ers : NFC playoffs: Redskins have improved since early-season loss in San Francisco.

Way back in September, before Earnest Byner turned into John Riggins reborn and Mark Rypien turned in a playoff victory, the Washington Redskins learned humility, 49er-style.

It was only the second week of the season in Candlestick Park, and the San Francisco 49ers did what they normally do--beat up on a weaker team. That time, the score was 26-13 on the strength of 467 yards of total offense.

But see what a little time, a playoff victory over the Philadelphia Eagles and a defensive line that looks meaner and more dominant every week can do for a team?

All of a sudden nobody remembers Sept. 16, and the Redskins are looking very much like the team that could knock the 49ers off their run of six consecutive postseason victories.

All of a sudden everybody remembers that Coach Joe Gibbs has a history of playoff success--Washington has won its last four playoff games--and that nobody is hotter than the Redskins now.

And when Washington gets hot, it tends to win Super Bowls--unless the 49ers are doing it themselves. Those teams have won the last three Super Bowls and five of the last eight.

So, yeah, September is a long time ago.

“We’re not playing the same team we were playing in the second week,” San Francisco Coach George Seifert said. “As we look at Washington now, they’re much more dominant and explosive defensively. They appear to have turned it up a notch.”

The 49ers haven’t had to do anything more strenuous than drive to work every day for the last few weeks.

While the Redskins have battled to get to this round, the 49ers have rested--and now they simply have to make sure it wasn’t on their laurels.

In their 20-6 whipping of the Eagles last week, one so decisive that it got Randall Cunningham benched and Buddy Ryan fired, the Redskin defense dominated the game, sacking Cunningham five times and playing excellent pass coverage.

That game was merely the capper to a sterling five-victories-in-six-games run, led by a defense that has allowed an average of only 271 yards. The pass defense that allowed Montana to throw for 390 yards in September has held opponents to an average of 189 yards passing over the last six weeks. Throw out its 35-28 loss to Indianapolis last month, and Washington has allowed only four touchdowns on defense during the stretch run.

“Our defense has bailed us out,” Gibbs said. “How we’ll match up against (the 49ers) again, you never know. But our defense has helped us get where we are right now.”

Defensive end Charles Mann said that the defense is set for the ultimate challenge: Shutting down Joe Montana and Jerry Rice and the rest of those players Super Bowl viewers have come to know and celebrate.

“We’re jelling,” Mann said. “We’ve been playing awfully well, and we’ve still got a lot more to prove.”

The 49ers’ defense knows that the Redskins aren’t a team with secrets. For the last six games, Washington has wound up Byner, given him the ball, and let him power through the holes carved out by the pile-driving offensive line, better known as “the Hogs.”

“The key will be the lines--both,” Seifert said. “Their offensive line vs. our defensive line, and our offensive line against their defensive line.”

For the Redskins, Rypien and the passing game amount to a secondary weapon, and Rypien, who has a 13-3 record in his last 16 games, has flourished.

“I really think Mark’s grown up,” Gibbs said. “You know, he’s still not very experienced as a quarterback in this league, and it takes time. But winning that last game was really important for him.

“That’s the name of this game. And he did it. He was poised and confident, and he did everything we asked of him. I’m very proud of him.”

NFC Playoff Notes

The 49ers activated wide receiver Mike Sherrard, a former UCLA player who suffered a broken right leg against Cleveland on Oct. 28. . . . The Redskins switched reserve quarterbacks, releasing Gary Hogeboom and activating Stan Humphries.