The Redskins had noticed it all week while studying San Diego game films: the Chargers repeatedly double-covered wide receivers on defense while dropping their linebackers deep into the secondary.

"There always was this open space right over the middle, just behind their defensive line," Clarence Harmon said. "It was always open. I thought they would adjust, considering we throw so much to our backs."

But San Diego stuck with the same defensive plan that had helped earn a 9-4 record this season. And the thankful Redskins, who pass to their running backs so much anyway, picked apart the Charger secondary with enough short tosses over the middle, mostly to Harmon and Wilbur Jackson, to help carve out a decisive 40-17 triumph.

This is how easy it was for the Redskins to complete a short pass on San Diego. Harmon already had caught 11 passes late in the game when Coach Jack Pardee was told he needed one more to set a club record. So Harmon went back into the game, ran a five-yard pattern over the middle and caught the Joe Theismann toss without a Charger within four yards of him.

"I really had 13," Harmon told Theismann with a big smile, "but you took one away when you accepted a penalty one time."

According to Pardee, "The Chargers aren't very sophisticated on defense. They line up and say, 'Try and beat us.' You just need time to read and throw to the right people."

Harmon said the Chargers tried to cover him mostly with middle linebacker Bob Horn. "There is no way a middle linebacker can run as far as he had to and still pick me up out of the backfield," Harmon said. "Most of the short stuff were option passes. I could break in or out, depending on how I was covered. They depend on their defensive line to put so much pressure on the passer that you can't get off the short stuff, but this time they failed."

The Chargers were leading the league in sacks coming into the game, but the battered Redskin offensive line did an impressive job holding them to only three for the afternoon.

The line knew it had to play well to protect the ailing Theismann, whose pulled hamstring hampered his mobility. Theismann probably should not have played, but Pardee felt the offense would not be able to function properly and keep pace with San Diego's scoring, unless he was in the lineup.

The Redskins reported the following injuries: tackle Dave Butz tore ligaments in his right thumb and he may need to have pins inserted in it; linebacker Monte Coleman sprained his wrist; Hermeling sprained his knee; tight end Rick Walker bruised his knee, and guard Jeff Williams burised a calf . . . Center Dan Peiffer played the whole game instead of injured Bob Kuziel . . . Joe Lavender's three interceptions tied the club record held by Pardee.