Just when it appeared the Redskins had written their own playoff obituary yesterday with a horrendous fourth-period collapse, Mark Moseley revived their hopes with a last-minute field goal that salvaged a 30-28 triumph over the St. Louis Cardinals.

Moseley's 39-yard kick with 36 seconds to go came only after holder Joe Theismann somehow plunked a ground-hugging low snap off the muddy RFK Stadium turf and set it down perfectly for Moseley's unerring toe.

Still, even this seventh Washington triumph in 11 games could not completely erase painful memories of those final 15 minutes, when Cardinal quarterback Jim Hart suddenly shrugged off an awful three periods and brought his team back from a 27-7 deficit to a 28-27 lead with 1:48 remaining.

"It would have been a crushing loss," Theismann said, looking back at those bleak moments when Hart was dominating with a streak of 11 successful passes on 1i attempts.

But the Redskins turned to their two-minute drill, which already had won two games this season, to send home happy the 508,868 wet and emotinally drained fans who braved the rain and chill.

The Redskins ended a two-game losing streak and improved their position in the NFC East. Dallas, 8-2, takes on Philadelphia, 6-4, tonight and the Redskins face the Cowboys next Sunday at RFK.

"We just have faith we can move the ball anytime we touch it in the last two minutes," running back Clarence Harmon said. He was right yesterday, but only because he and tight end Don Warren turned in spectacular catches during the ensuing 72-second span.

The Cardinals, however, made one more desperate attempt to set up their own field goal and salvage the game that once seemed far beyond their reach.

After a kickoff return to the St. Louis 48 with 27 seconds to go, Hart found running back Ottis Anderson for eight yards. Rookie linebacker Monte Coleman knocked down a toss to Anderson on second down and Tony Peters almost picked off a third-down throw. On fourth down, tackle Dave Butz, fittingly a former Cardinal, swatted away Hart's barely launched pass. The Redskins had beaten the Cards home and home this season.

The Redskins are fully aware it should never have come down to Moseley's kick, his third field goal of the day in three tries. For three periods, they had everything their own way. They moved the ball on the ground, they caused mistakes (four St. Louis turnovers) and they controlled the clock.

Two of those turnovers (interceptions by Lemar Parrish and Joe Lavender) set up field goals and three impressive drives led to two touchdowns by John Riggins (a seven-yard run and a four-yard pass from Theismann) and one by receiver Ricky Thompson (on an eight-yard Theismann pass to close out a two-minute drive at the end of the first half).

But the offensive coordinator, Joe Walton, admitted he might have become too conservative in his fourth-quarter play-calling and for three series Washington couldn't even gain a first down.

Hart capitalized on the Redskin letdown -- and sorry pass rush -- and began picking apart the secondary, driving his team for three scores within eight minutes. The last was a 21- yard touchdown grab at the 1:48 mark, by Anderson (who rushed for 105 yards on 25 carries to bring his rookie total to 1,105 yards).

When Steve Little added the extra point for a 28-27 lead, Coach Bud Wilkinson's Cardinal bench erupted in joy and the Redskins gazed at the ground, not believing what they were seeing.

By the time Theismann and company trotted onto the field, 103 seconds remained on the clock and the Cardinals goal line was 80 yards away.

"I thought we could drive and win the game," Coach Jack Pardee said. "I've got that much faith in our two-minute offense. It's been good to us all season." (It delivered a touchdown in today's second quarter.)

Theismann, who was so sick with flu Saturday that the team didn't practice the two-minute sequence as it normally does, immediately found himself in an even deeper hole.

The Cardinals, taking advantage of rookie tackle Greg Dubinetz's inexperience, worked a stunt that left lineman Mike Dawson free to sack Theismann cleanly for a nine-yard loss. Dubinetz was playing for Terry Hermeling, who had suffered a possible elbow dislocation in the first half.

Theismann got the loss back on a nine-yard toss to Harmon, but he was faced with third and 10. And everyone in the stadium, especially the Cardinals, knew he had to throw.

The play call was "95 A and B out." Warren slanted into the middle while the Washington running backs cut to the outside, taking linebackers with them.

"I was covered by Roy Green man to man," Warren said. "I took him up 15 yards and then came back Joe said the ball slipped. I don't know, it was a bit high but it looked good to me."

The pass hit Warren on the hands between two defenders. He said the fact his thumb was heavily taped to protect a sprain suffered last week against Pittsburgh (the same thumb fractured at a minitraining camp in May) prevented him from clamping the pass immediately.

"I think it hit the tape," Warren said. The ball bounced straight up and he saw the defenders converging on him. "I watched it all the way and just grabbed it when it came down," he added with a large smile.

Warren wound up with a 14-yard gain and a Redskin first down. For the rookie, who played the entire game instead of alternating, as usual, with Jean Fugett, it also meant his first game ball, "which is probably the biggest moment in my life right now."

It meant continued life for Washington. The clock was still running and the Cardinals lingered getting back to the line of scrimmage. Finally, with 1:09 to go, Dawson was called for delaying the game, moving the ball to the 39.

"We were taking what they were giving us," related Walton, who lets Theismann call the plays in these two-minute exercises in drama. "That means going in the middle or to the sides and staying away from going deep."

Theismann next turned to Harmon, who last month pulled in the game winning touchdown against Cleveland. Both Harmon and Warren were potential passing targets on the first-down play, but Theismann, under a heavy rush, spotted Harmon slightly open on the right sideline, in front of the Redskin bench.

"The tight end (Warren) goes inside and hooks and I go outside and hook," Harmon said. "Joe sees where the safety goes. The one who isn't covered gets the pass."

Theismann's toss weas low -- "knee high," Harmon said -- and hard. Somehow, the quiet man from Kosciusko, Miss., reached down, controlled the pass with his fingertips, pulled it in and streaked away from startled linebacker Mark Arneson.

"He (Arneson) couldn't see the pass coming, he had his back turned to Joe," Harmon said, "but I could see it all the way. That gave me the advantage."

Harmon turned the spectacular grab into a 35-yard gain and another first down, this one at the Cardinal 26. St. Louis took a timeout with 55 seconds remaining.

On the Redskin bench, Pardee told Walton to try to get the ball closer to the Cardinal end zone, just to give Moseley some leeway. Two passes by Theismann fell incomplete before Ike Forte slanted up the middle for four yards, bringing up fourth down at the 22-yard stripe.

Moseley, the NFC's leading kicker and perhaps the steadiest in all of pro football, nailed the field goal. But he and his teammates gave just as much credit to Theismann for his marvelous ability to handle Ted Fritsch's low snap.

"He's the best bad-snap holder in football," Pardee said. "But I didn't celebrate. All I thought about was St. Louis still had all that time to score."

But the Cardinals didn't score and the Redskins are that much closer to a wild-card playoff berth. There will be some deep thinking, however, at Redskin Park this week about what brought on the fourth-period collapse.

"You can't let down on a team like the Cards," Pardee said. "A guy like Hart, he can miss eight or 10 and then get hot and run off 12 in a row. They are so explosive. You let down and you are in trouble."

As long as the Redskins gave Hart time to pass, he was able to pinpoint his receivers, even against the tight coverage of the secondary.

Earlier, bothered by some pressure, Hart had thrown two interceptions to Parrish and one to Lavender. Those mistakes, together with a fumble by Anderson into the Redskin end zone in the first period, recovered by Parrish for a touchback, put St. Louis into a deep, deep hole. Between his special-teams duty and linebacking stints, Coleman helped hold them there with 11 tackles.

Hart and the Cardiac Cards began the climb back with Little, passing from punt formation, picked up a first down on a 15-yard toss to Green. St. Louis didn't score on that series but the Redskins found themselves in bad field position, a problem that would continue to plague them.

A roughing-the-passer penalty on Butz helped the Cards move to their first touchdown of the fourth period, a two-yard run by Wayne Morris. Three quick completions led to another touchdown, a one-yard plunge by Theotis Brown. And an incredible, backpedaling, over-the-head 24-yard reception by Pat Tilley -- "one of the all-time great catches," Pardee acclaimed -- set up the go-ahead score. "We are only human," said Parrish, who played with a protective vest over sore ribs. "Things like this do happen. He's a fine quarterback and he's done this before."

Hart finished with 16 completions in 36 passes for 178 yards after starting five for 21. Theismann was much steadier (16 for 28, 197 yards", mixing up his passes to seven different receivers.

"It wasn't very graceful, but I'll take it," Pardee said. "This shows something about our team. These people never give up."

But his athletes do get scared.

"Yes, I was scared to death when I saw that snap," Thompson said."Joe just made a heck of a play. I'm glad I kept my eyes open to see it."