The Redskins wouldn't allow even an eight-week strike to interrupt a remarkable start to this NFL season, as Joe Theismann threw for two touchdowns and Washington defeated the New York Giants, 27-17, today, running its record to 3-0.

In past years, Theismann would come into Giants Stadium near his boyhood home and try to perform miracles. Today, he said he merely wanted to think clearly "and not do anything foolish.

"It's not all what Joe Theismann can do anymore or how spectacular a play Joe Theismann can make, because those days are gone, I hope," said Theismann. "Now, I'm playing as well as I've ever played, and that makes me very happy."

And the Redskins, strike or no strike, have become a legitimate playoff contender, even at this stage of what will be a nine-game regular season -- barring another stoppage, as they head into their first game in RFK Stadium since last December, next Sunday against Philadelphia.

Washington now has defeated three 1981 playoff teams (Philadelphia, Tampa Bay and New York) on the road, a feat Coach Joe Gibbs described as "beyond anything I could have imagined. If someone told me we'd be 3-0 against these teams, especially after the long layoff, I would have said, 'Hey, be truthful, no way.' "

But it's happened, mainly because Theismann somehow maintained his touch through the long weeks of the strike and John Riggins had the stamina to carry the ball 28 times for 70 yards and a touchdown.

Theismann has not thrown an interception in 83 passes this year, never even coming close today against the 0-3 Giants, who have one of the league's premier defenses.

He completed 16 of 24 for 185 yards. He was sacked only once despite decent pressure, which he avoided for the most part with some timely scrambles that kept rescuing the Redskins at the most opportune moments.

"When a quarterback starts to improvise, that causes problems for the secondary," Giants cornerback Terry Jackson said. "Theismann was improvising all day. The bottom line is to stop his passes and we didn't do it. He just gets out of the pocket so quickly."

Gibbs was so apprehensive about how his team would play today that he said he felt "more pressure than any game we played this year and most last year. We had so much going for us before the strike and then losing our home games (to the reduced schedule) . . . This was a big test for us, to see if we could get the old feeling back, to see if we could forget the strike and pick up where we left off."

But his players started off as if there never had been a strike. Less than 19 minutes into the game, the Redskins were ahead, 21-0, and the crowd was filling the stadium with boos. At halftime, after New York could score only a field goal, many Giants fans stood and angrily chanted, "Strike . . . strike . . . strike," at the home players.

The Giants had enough problems already, trying to stop Theismann, who credited frequent workouts the last two months with teammates at a Reston, Va., playground for his effectiveness.

"We put ourselves in a hole," said Giants linebacker Brad Van Pelt. "Then, they dictated what the game would be like."

The dictation came early. On their first possession, the Redskins moved 73 yards in 12 plays, Theismann completing four passes and receiver Art Monk running 14 yards on a reverse. Virgil Seay pulled in one completion for 34 yards, after bobbling the ball four times. And Charlie Brown almost had his fourth touchdown catch, but was downed at the one after a 13-yard gain.

Three plays later, Theismann and fullback Otis Wonsley teamed up for a one-yard scoring pass. Wonsley's first reception of the season, plus Mark Moseley's conversion, gave Washington a 7-0 lead with 9:27 left in the first quarter.

It was soon 14-0. Brown ran a simple slant pattern against Jackson, who missed an ankle tackle when the Redskin receiver made a sharp pivot at the Giants' 30. Brown then outraced Beasley Reece down the left sideline to the end zone flag to complete the 39-yard play.

"They were playing a lot of nickel and dime defenses and that was surprising," Theismann said. "We got them in one-on-one coverage a lot." Said Brown: "I just love that end zone."

Theismann and friends then got a little help from the Redskins' defense. Quarterback Scott Brunner, under pressure from a blitzing Mel Kaufman, threw behind tight end Gary Shirk. The ball bounced off Shirk's hands and was intercepted by Dexter Manley, who returned it to the Giants' 18.

A scramble by Theismann, who used a fine block by Russ Grimm, got the ball to the two. Fullback Riggins bulled over from there, again behind Grimm. Moseley's kick made it 21-0 with 11:17 remaining in the second quarter.

"I can't explain the fast start," Gibbs said. "I was surprised we played so well. I thought we were rusty, but we had good execution."

Even though the Redskins wound up winning their sixth straight over two years (and 11th of their last 14), the game became a lot closer than it should have been, thanks to a third-quarter blocked punt that finally got the New York fans cheering instead of complaining.

"My fault," said the special teams coach, Wayne Sevier, about Frank Marion's block of Jeff Hayes' punt. "I had them in man-to-man blocking and they should have been in zone."

Larry Kubin, the last blocker protecting Hayes, never saw Marion. The Giants recovered at the Washington 26, from where Brunner threw a touchdown pass to Johnny Perkins.

"We were lucky to hold them off after the block," said free safety Mark Murphy. "They got rolling, but I thought the defense finally did what it needed to do."

Moseley's 37-yard field goal, his seventh in a row this season, increased Washington's lead to 24-10 with 53 seconds left in the third quarter. But the Giants answered with Cliff Chatman's one-yard touchdown run to pull within seven points with 12 minutes to go in the game.

The Redskins then turned to Riggins. He had 10 carries the rest of the quarter, enough to set up a 29-yard Moseley field goal while also eating up valuable time. And the better he ran, the better the Washington pass rush became. The front four pressured Brunner in the final minutes, forcing bad passes and causing two sacks, by Tony McGee and Dave Butz.

"I think the Giants played very conservatively," Manley said. "I got tired at times out there, but I think we were hungrier than they were. We had better preparation."

The Washington defense seemed to be tiring in the fourth period, but tackle Perry Brooks said the unit "got a lift from the way the offense was controlling the ball. It kept us off the field."

Said Gibbs: "Defensive improvement is the biggest change in this team. I don't feel helpless anymore when the other team has the ball. They are able to stop people now."

But the Redskins still would not be 3-0 without Theismann's play. He was particularly instrumental in keeping the offense together during the strike. He organized practices for the passing game and became an unofficial coach of the workouts, which ended two weeks ago.

"We just wanted to come out of this as a team, just like we were before the strike," said Theismann, who seems to have profited most from the work.

Gibbs, who previously has coached Jim Hart and Dan Fouts, said that "Joe is playing about as good as I've had anybody play . . . I can feel him on the bench now, the way he has control of the game and himself.

"Joe is really maturing as a quarterback, he's confident, he understands what he is doing. But what I am pleased most with is that he isn't forcing things to happen. He's scrambling or throwing the ball away instead of trying to force something to happen."

Someone said Gibbs appeared relaxed instead of being overly excited.

"I'm relieved," he said. "It's been a crazy week. A real crazy week. I'm glad it's over."