After three weeks of dominating play by the Redskins, Coach Joe Gibbs yesterday said any playoff opponent will have to produce "a very good game" to beat his team, as long as Washington continues to have virtually error-free performances.

"The key now is ourselves," said Gibbs, whose team will play the Minnesota Vikings Saturday at 12:30 p.m. at RFK Stadium in the next round of the playoffs and is two victories from playing in the Super Bowl. "We have to play our game--no turnovers on offense, play hard on defense and have good special teams. It's more us, if we concentrate on ourselves and not worry about the other team.

"Certainly any team we play from now on is capable of beating us. If we play our game, we will be hard to beat. Someone is going to have to play a very good game against us . . . If we don't cause our own problems, certainly our odds go up."

The Vikings were on the Redskins' regular-season schedule, but the Nov. 14 home game was canceled because of the players strike. Gibbs said his staff "had studied films of the Vikings during the strike, but will get to work on them more Monday. I saw enough of them last Monday night (against Dallas) to know they are very good and are very dangerous."

Gibbs was upset that the Redskins had to play Detroit on a Saturday, but said he had no complaints about a Saturday game this week. "We are in a regular work schedule and routine now," he said.

Gibbs acknowledged his team's last three opponents--New Orleans, St. Louis and Detroit Saturday--aren't among the league's best. That is the one question mark still surrounding the Redskins: can they beat one of the elite?

But, as safety Tony Peters said, the Redskins are on a roll. Even though injuries have limited Gibbs' offensive plans, Washington is doing what it couldn't accomplish earlier--decisively defeating weaker members of the National Football League.

The Redskins have been successful in part because of a combination of team chemistry and good fortune.

Ahead are only teams with winning records, but Washington is peaking at the right time. Consider:

In the last three weeks, the Redskins have outscored opponents, 86-17. They've had large advantages in total yardage (1,067 to 757), sacks (14-10) and rushing yards (502-256). They've caused more turnovers (11-2).

Gibbs wants his offense to control the ball, especially by running well. The Redskins have had five straight games of more than 100 yards rushing, including a 175-yard effort against Detroit, which had the NFC's top-ranked rushing defense. The Redskins are making few mistakes, and their highly aggressive defense is creating havoc with opponents' offenses, especially deep in Washington territory.

Two key offensive players, Joe Theismann and John Riggins, are playing particularly well.

Theismann has thrown 82 passes over the last 3 1/2 games without an interception and has five touchdown passes in three games. His 73-percent accuracy against Detroit was the third-best of his career. Riggins, after two weeks of limited activity, overpowered Detroit tacklers with his hard running, gaining 119 yards.

Defensive Coordinator Richie Petitbon's gambling, blitzing tactics finally have given the Redskins a consistent, sometimes devastating pass rush, one reason the secondary has six interceptions in the last three games. Washington is combining sophisticated line stunts with blitzes from the linebackers and defensive backs, confusing offensive line assignments and opening up unimpeded lanes to quarterbacks.

"With the way the rules give the offense all the advantage on passing, you have to go after people or you just won't get to the passer," Petitbon said. "And if you don't get to the passer, he'll kill you every time."

In the last three weeks, the special teams haven't given up a punt return longer than eight yards or a kickoff return longer than 33. In contrast, Mark Moseley is the league's best field goal kicker and Mike Nelms, the NFC's Pro Bowl kick returner, came close to his first scoring return of the season Saturday.

Each week, Gibbs learns something new about his team. After the way defensive tackle Darryl Grant and receiver Alvin Garrett have stepped in for injured teammates, there is less concern about depth. Just as important, the offense performed effectively against Detroit despite the loss of receiver Art Monk and the scrapping of the three-receiver portion of Washington's game plan.

"Considering everything, I thought we played pretty well on offense," Gibbs said. "I don't know how much it hurt us not to play with three wide receivers. Normally we do that on all third-down, long-yardage situations.

"We're developing a confidence in ourselves, and a hardness. We believe we can get the job done. And we're excited, too. But we still don't know what long-range effect not having Art Monk will have on us."

Gibbs should be able to use three receivers this week. Virgil Seay has recovered from hip problems and is expected to be ready . . . Neal Olkewicz (knee cartilage) and Quentin Lowry (sprained ankle) are the two most seriously injured Redskins after Saturday, but Gibbs and trainer Bubba Tyer expect them to play this weekend . . . Gibbs said unless Joe Washington's sore knees improve, he'll probably be limited in the playoffs to long-yardage receiving out of the backfield. Washington has bone chips in his right knee that will require arthroscopic surgery after the season . . . Wilbur Jackson becomes Riggins' principal backup on running plays.