Washington Redskins quarterback Mark Rypien sat in front of his locker in one corner of a muggy dressing room almost an hour after Friday night's game, explaining to wave after wave of reporters that, yes, he'd made some mistakes.

He was patient and thorough and scolded himself before anyone else had a chance to, saying in part: "I always get on myself when things aren't going well. I started off well, but didn't even show up in the second half. You have to play smart and I didn't. That second interception was a cardinal sin for a quarterback and you just can't have that."

The Redskins defeated the Pittsburgh Steelers, 27-24, in a preseason game Friday night at RFK Stadium. They won thanks to a defense that scored a pair of third-quarter touchdowns and in spite of an offense that again never got going.

For a second straight week, Ryp-ien again had some moments of brilliance and some mistakes he would rather forget.

In a 31-27 loss to Atlanta a week earlier, he'd had a stretch when he'd been almost perfect in taking the Redskins on an efficient 76-yard drive. He'd completed four of five for 67 yards and finished the drive with a 22-yard touchdown toss to Gary Clark. He was just four for 14 the rest of the game.

It had been much the same Friday night when, early in the second quarter of a game played for some time under half light because of a stadium electrical problem, he'd gone five for five (74 yards) in taking the Redskins on an eight-play, 88-yard stroll through the Steelers' defense.

But the rest was a nightmare as he completed six of 15 otherwise and threw a couple of interceptions that aren't likely to look much better when his coaching staff breaks apart the film today.

Redskins Coach Joe Gibbs has kept most of his regular-season offensive package limited to the practice field so it's hard to tell exactly how bad or how well people are playing. However, with Rypien, the numbers after two weeks -- 19 of 39 for 273 yards for two touchdowns and two interceptions -- tell of his struggle.

"We still have to keep working and banging away to find the right chemistry that will get us what we want," Rypien said. "Both our running and passing still need a lot of work. I've been pressing a little bit, trying to get myself going. I've had a couple of situations where I tried to make something good out of something bad and there's really nothing worse you can do."

Rypien's performances are more noticeable because the Redskins haven't had a running game to fall back on. The slump that began last season and resulted in the bombs-away offense has continued into this preseason and shows no signs of improving.

The Redskins have rushed the ball 47 times in two games and averaged 2.5 yards per snap. Their only bright spot Friday was again rookie Brian Mitchell, who carried eight times for 45 yards, but also nearly fumbled the game away with a fourth-quarter drop that became a Pittsburgh score.

Earnest Byner had the night off because of a sore hip. That gave Gerald Riggs a longer look and for a second straight week he had problems, carrying the ball seven times for 23 yards. In two games, he has carried 16 times for 35 yards. His longest gain has been eight yards.

James Wilder, the Plan B signee, rushed four times for seven yards Friday night and has eight carries for zero yards in two weeks.

"The running game is sputtering," Gibbs said, "and that's part of the problem with the passing game. It all works together. I still feel good about the offensive line and the running backs, and we've got to find a way to get it going. We have a long way to go. I know we're playing hard. I know we're trying. It's just not there yet."

The good news is that he still has three weeks to get it there. The other news is that the Redskins finish this preseason with three 1989 playoff teams, and as Rypien said: "I still think we're making progress. Remember, we aren't playing Sisters of the Poor and the bottom line is we did get a victory. The defense bailed us out and hopefully we can do it for them down the line."

The Redskins return to training camp in Carlisle, Pa., Sunday night and will work there for about four more days before heading to Redskin Park to prepare for the final two preseason games -- at Cleveland next Saturday and against the Los Angeles Rams at RFK on Aug. 31.

Rypien made his mistakes at the end of the first half and the beginning of the second. The first came with 3:24 left in the second quarter and the Redskins at the Pittsburgh 43.

On second and 10, he dropped back and looked for Kelvin Bryant in the left flat. He found Bryant, but defensive end A.J. Jenkins read the play, stepped in front of the receiver and returned the ball 31 yards down the sideline. Bryant saved the touchdown with a tackle, but the Steelers got it four plays later to cut a 10-0 lead to 10-7.

The first half ended that way, after a Rypien fumble forced Washington to punt, and the second opened with Rypien making another bad decision, overthrowing Terry Orr and finding safety Darryl Holmes. That set up Gary Anderson's 51-yard field goal to give the Steelers a 10-10 tie.

But the Redskins were about to make a couple of plays that saved their night. Defensive lineman Pat Swoopes tipped a Randy Wright pass into Monte Coleman's hands and Coleman sailed 50 yards untouched for the score and a 17-10 lead.

Pittsburgh's Dwight Stone fumbled the kickoff and fell on it at the 1. Another new Washington defensive lineman, Alonzo Mitz, knocked the ball out of rookie runner Barry Foster's hands on the first play from scrimmage, and safety Clarence Vaughn jumped on it in the end zone for a 24-10 lead.

"We still don't have our starting defensive unit in," Coleman said. "But we said before the game we were going to try to jell as a unit tonight. The guys played hard and we really have to feel optimistic."

Vaughn hadn't scored a touchdown since high school, and after the game, had hidden the souvenir ball in his locker.

"That one's special," he said. "You forget what it's like to score a touchdown. I guess I'm going to have to work on my spike. This game has to help the defense a lot. We stepped it up a bit and showed we could make some plays. We had injuries at the end of last year and still played pretty well. You have one game like this and you know you can do it again."

Redskins Notes: The Redskins got out of a second straight game with no serious injuries. Linebacker Brian Bonner suffered a sprained left knee and may miss a few days of practice. Middle linebacker Greg Manusky has a bruised left hand and H-back Jimmie Johnson a stinger in his left shoulder. Johnson and Manusky probably will practice on Monday.