Joe Theismann helped put some fun and frolic back into the Redskins offense yesterday and when the Washington defense came up with the key plays at the end it all amounted to a 23-17 victory over the Philadelphia Eagles.

There were many smiling faces and fluttering hearts among the RFK Stadium crowd of 55.031 as Theismann quickly stamped his first start of 1977 memorable. He winged two quick 15-yard touchdown passes to Jean Fugett on the Redskins' first two possessions.

Those points, three Mark Moseley field goals and some inspired defense in the final 12 minutes allowed the Redskins to improve to 43 at the halfway point of the season, tied for third-best record in the National Football Conference.

With the Cowboys 7-0 and the Vikings 5-2, the Redskins, Rams and Falcons all are 4-3, with the Cardinals and Giants. Monday night foes, 3-3. It is going to be a very wild race for the wild card.

Theismann - so what else is new - came out pitching yesterday. He passed on 27 of the Redskins' 41 first-half plays. For the game, he completed 16 of 34 for 218 yards, a set of statistics that would have been more impressive save for those old nagging mistakes.

Victory achieved, Theismann mostly thinked his beleaguered and lately maligned offensive line, even if he was sacked five times. Taking over for benched Billy Kilmer, he helped produce 312 yards of total offense.

"I'm as happy as I could be," Theismann said. "But a passer is nothing without time, and the offensive line did a great job. Those guys have taken a lot of flak, and they hung in there. They just did the job and created the situations for me."

Yet there were several of the typical foul-ups that have plagued the Redskins all season.

On one bizarre possession, the Redskins took a 50-yard Moseley field goal off the board after the Eagles roughed the kicker; had a 15-yard touchdown pass to Calvin Hill nullified by a holding call on Terry Hermeling, and had an apparent 25-yard touchdown pass to Danny Buggs wiped away because Theismann stepped out of bounds just as he passed.

Even if Theismann had managed to stay on the field, the catch wouldn't have counted because the Redskins had too many men at the line of scrimmage and were called for an illegal formation. What will they think of next?

Oh yes, another apparent 34-yard touchdown catch by Buggs in the third quarter was called back. It seems taht Buggs ran a most unusual pattern, down the left sideline out of bounds, then back on the field.

It may work on the playground, but not in the NFL.

The Redskins were penalized only four times in all for 35 yards, their season low. But every call, as usual, came at a most inopportune time.

Because of botched opportunities like that, the Eagles were very much alive after Harold Carmichael caught a 48-yard touchdown pass from wounded Eagle quarterback Ron Jaworski (broken right thumb) to cut the Redskin lead to 23-17 with 11:58 remaining.

So the Redskin defense began asserting itself, particularly on the Eagles' final two possessions in the last six minutes.

Gerard Williams, the second-year cornerback expected to replace Pat Fischer permanently, eventually came up with his second interception of the day on a diving catch at the goal line intended for Eagle receiver Charles Smith.

"It was just one-on-one coverage and the ball was underthrown," said Williams. "Yeah, they were picking on me. They'll pick on me all year because I'm the new man, but as long as I keep making interceptions, who cares.

The Redskins claimed the ball at their two-yard line, failed to make a first down and asked Mike Bragg to punt from deep in his end zone. His 43-yard kick set the Eagles up at the Redskin 33, and it was trauma time again at RFK Stadium.

A 21-yard pass from Jaworski to Smith gave the Eagles first down at the Washington 20, and emergency rooms around town probably were gearing up their coronary units. They need not have bothered.

On first down, with 1:25 left, Jaworski threw the ball away when Williams and Eddie Brown were all over Smith, the primary receiver.

On second down, with 1:09 remaining Bill Brundige thundered through the middle and sacked Jaworski for a 10-yard loss. On third down, Jaworski's pass intended for tight end Keith Krepfle in the end zone was broekn up by nickel back Brig Owens.

And on fourth down, with the entire stadium on its feet and George Allen practically a basket case on the side-line, Brundige and Brad Dusek came swooping in on Jaworski. Dusek leaped high in the air like a Dr. I in cleats, and batted the Eagle quarterback's final pass to the turf.

"That sure felt good when it hit my arm," Dusek said. "At first he just dropped back, but the line forced him out of there and the guy I was supposed to be covering went back the other way. I saw someone else over there and I knew he couldn't get the first down if he caught the ball, so I just went for the quarterback and got lucky."

Theismann, who spent 45 minutes heaping praise on his teammates in the locker rooM also was fortunate.

Several times he threw the ball up for grabs, including one toss in the second period to Calvin Hill that hit Eagle cornerback John Outlaw in the hands and fell to the ground. Only [WORD ILLEGIBLE] yards of open field by between Outlaw and a touchdown.

The crowd didn't mind as Theismann scrambled frequently, whirling away from Eagle defenders, running four times for 21 yards and doing joyful dances after each of his touchdown passes to Fugett.

Both scores came as a result of excellent field position. Tackle Diron Talbert forced a Tom Sullivan fumble on the Eagles' first play from scrimmage and Ken Houston recovered at the Philadelphia 44.

A 12-yard pass from Theismann to Frank Grant on third and seven preceded Fugett's first touchdown catch, via a simple post pattern and a Theismann speedball.

A 16-yard Spike Jones punt on the following Eagle possession gave the Redskin offense the ball at the Philadelphia 29. An 18-yard pass to Buggs and a four-yard reception by Mike Thomas on third and three set up the score.

On second and 15, after a sack, Fugett ran the same pattern as his previous touchdown reception and caught another hummer from his quarterback.

All that was accomplished barely seven minutes into the game, but Philadelphia yanked the Redskins back to reality with a 79-yard, 11-play touchdown drive on the next possession -- all the yardage coming on the ground.

James Betterson's 16-yard touchdown burst cut the lead to 14-7.

Until Carmichael's fourth-period touchdown catch, the only points thereafter were provided by Moseley's three field goals adn a 44-yard place kick by the Eagles' Horst Muhlmann.

Moseley attempted three other kicks, a 49-yard shot that was short in the second period, a 47-yard boot early in the fourth that hit the right upright and bounced wide right, and a 54-yard kick that was off target midway through the fourth quarter.