In one of the most dramatic moments in Redskin history, Mark Moseley secured both a playoff spot for his team and a National Football League record yesterday with a 42-yard tipped field goal that wobbled over the crossbar with four seconds left.

Moseley's kick, his third straight of the snowy afternoon, pulled out an emotional 15-14 victory over the New York Giants, now 3-4. It was Moseley's 21st in a row over two seasons, breaking Garo Yepremian's NFL record set in 1978-79. And it came just as Moseley had hoped it would, with the game at stake and RFK Stadium trembling with excitement.

"It was the most exciting moment in my life, other than getting married and having my children," said Moseley, who was mobbed by his teammates as soon as the ball ended its journey. "It was the first time I got overly excited (during the streak). For some reason, all week long I felt it would be a big game and it would come down to a field goal."

Moseley almost didn't survive a challenge in training camp by rookie Dan Miller. Now he has the one record he really wanted "because I hope to be known as a consistent kicker and 21 straight says I'm consistent."

The Redskins, now 6-1, reached their primary regular-season goal, their first playoff berth since 1976. They also are on the verge of securing the home-field advantage for at least the first-round game. In five of those victories, Moseley's field goals (he has 18 this year) have been the margin of victory.

"It was like a Hollywood script: you couldn't have written it any better," safety Mark Murphy said. "We knew Mark was going to make it. I've seen him do it in that situation so many times. It was just unbelievable, but we've gotten to a point where we expect to win."

The Redskins won despite five first-half turnovers, including four interceptions by Joe Theismann. But they received a superb effort from a defense that limited the Giants to 139 total yards and from fullback John Riggins, whose 87 yards on 31 carries also were significant.

Riggins, who had 15 attempts in the fourth period, is only the fifth NFL player to have at least 2,000 carries. He is the eighth to gain more than 8,000 yards rushing and the 24th to go over 10,000 combined yards (rushing, receiving and returns).

But until the final 3 minutes 28 seconds, the Giants appeared to have the game won, in part because the more dominant Redskins (375 total yards) once again couldn't convert opportunities into touchdowns.

New York's first interception led to a 28-yard touchdown pass from Scott Brunner to Johnny Perkins in the first quarter. A 20-yard field goal by Moseley, after Washington had a first and goal at the eight, cut the lead to 7-3. But New York's third interception set up a one-yard score by Butch Woolfolk with 14 seconds left in the first half to stretch the lead to 14-3.

"I told them at the half that we were fortunate not to be further behind," said Redskin Coach Joe Gibbs. "I told them that if we could put together one pounding, sustained drive with a lot of plays and score a touchdown, we'd be right back in the game."

His players responded by turning their first possession of the third quarter into an 80-yard, 10-play scoring drive that ended on a 22-yard run by Joe Washington.

But even that play didn't work the way Gibbs wanted. Washington was supposed to start a sweep around right end, then pull up and throw to Art Monk. But the Giants had the play defended against well and Washington had to ad-lib. He reversed direction and cut back left.

"I saw one friendly jersey and it was Joe Theismann's," said Washington. "Then I had to get by one Giant or flip the ball to Joe, like a wishbone quarterback." Theismann made the choice easy by taking out Terry Jackson with a fine body block, allowing Washington to win a foot race to the end zone.

Moseley, however, missed the extra point when the ball slipped off his wet toe and the Giants led, 14-9, with 8:14 remaining in the third period.

It then became a matter of how long New York could hold on. The Redskins shut off New York's running game, forcing young Brunner, who has a sore throwing thumb, to pass. He was erratic (10 of 26, 128 yards), mostly because Washington blitzed him almost every way possible, sending linebackers and safeties in various combinations. The result was three second-half sacks (after one in the first half), including one by linebacker Rich Milot, who had three for the day.

"Brunner takes a short drop, so the only way to get pressure on him was to blitz," said safety Tony Peters. "I think we rattled him. We just didn't want to let this one get away. I've never been in the playoffs and I wanted it bad."

The Giants had the ball for only nine minutes after the half and could gain just 42 total yards (17 on the ground) against the swarming Redskins, whose secondary batted down seven passes. Three were by rapidly improving rookie cornerback Vernon Dean.

Theismann, who saw one first-half scoring opportunity end when Monk fumbled a 29-yard pass at the Giant three, had two front teeth chipped in the third quarter on a sack by linebacker Byron Hunt. But he stayed in the game and directed the Redskins to a 31-yard field goal by Moseley that ended a 51-yard drive early in the fourth quarter and tied Yepremian's record. Riggins carried eight times for 42 yards during the drive.

Following a punt by the Giants, the Redskins faced a fourth and one at their 40. Gibbs decided to go for a first down, but the Giants, and everyone else in the stadium, knew Riggins would get the call. He did, and lost two yards.

On the Giants' ensuing possession, linebacker Mel Kaufman sacked Brunner for seven yards. Murphy, Neal Olkewicz and Larry Kubin then dropped him for 11 more to force another punt.

The Redskins took over at their 29 with 3:28 left. On second down, Gibbs went with the Dallas special, a multipatterned play that sprung tight end Rick Walker open across the middle for a 20-yard gain. Washington had a first down at the Giant 44 after cornerback Beasley Reece was called for a face-mask infraction.

"That play was something I had down just for a time like that," said Gibbs. Added Walker: "The Giants played just the defense we wanted. Charlie Brown ran a hitch pattern and everything opened up for me. It was scary. I thought any moment someone was going to pop up and put me into next week."

Two plays later, Gibbs turned again to Theismann, who had tied a personal record with his four interceptions. "I made a mistake on each one and I knew what it was," said Theismann. "So there was no reason to lose confidence."

Theismann finished with 25 completions in 38 attempts, the fourth-best completion day of his career, for 252 yards.

Theismann completed a seven-yard pass to Brown, then a fine 14-yarder between two defenders, also to Brown, who had seven catches for 96 yards. Washington had a first down at the Giant 25.

"I wanted to get inside the 30, at least, for a field goal," Gibbs said. But when Riggins ran to the 19 and then to the 13 for an apparent first down, Gibbs began thinking touchdown. However, Walker was called for holding on the second carry, pushing the ball back to the 29.

With 58 seconds to go, Riggins went off right guard for five. With 45 seconds left, he lost a yard trying to get around right end, pushing the ball back to the 25. The Redskins let the clock run down and then called time with nine seconds left.

Moseley trotted on the field. During the streak, he already had made four kicks longer than the 42-yarder he faced. And he had kicked in worse weather, even though the snow was falling rapidly now. This time, the snap from center Jeff Bostic was good and Theismann's hold was perfect.

Hunt, the Giants linebacker, leaped as the kick took off and touched the ball with his fingertips. The ball turned over and wobbled but Moseley said he hit it better than any other attempt this season. The kick cleared the crossbar with only a couple of yards to spare.

"I said to myself if we are going to win, we're going to win with Mark, or we are going to go down with him," Gibbs said. "He's gotten us here, just like Riggins has gotten us here. I just got down on one knee and said a prayer before he kicked it."

Moments later, the field was swarming with Redskins. And the Giants were standing, heads down, cut off once again by Moseley's success.