The post-mortem at Redskin Park yesterday was lengthy. Blame was sprinkled generously, except on the offensive line. Answers, many seeming so empty, rolled in slowly, like the afternoon's thunderstorm. Shock was late in wearing off.

"You don't know why things like this happen," Coach Joe Gibbs said of the Washington Redskins' 44-14 season-opening loss to the Dallas Cowboys Monday night. "I'm convinced you probably could come up with 100 reasons why we played like this. I'm not sure there are just one or two."

But, somewhat surprisingly, it became clear that quarterback Joe Theismann, who threw a personal-record five interceptions during 15-for-35 passing, will not receive most of the blame from the coaches, nor from himself.

Theismann, who went through a short afternoon workout in red sweats, said he disagreed "vehemently" with a reporter's suggestion that he played the worst game anyone can remember him playing.

"The statistical results were not very much in my favor, but I felt like I threw the ball very well," he said. "I didn't feel like I threw many errant passes at all. I felt like most of them were pretty damn close to my receivers and even the ones that were picked off were mighty damn close to the guys that were supposed to have the football."

Theismann said a "couple" of the later interceptions were his fault.

"Toward the end of the game, I probably fell into the old quarterback profile -- that's to try to get too much, to try to make things happen yourself," he said.

"A couple throws I made I would have been better off dropping off or throwing away, the ones that resulted in interceptions or the one for the touchdown (Victor Scott's 26-yard return late in game)."

But, the Dallas pass coverage, a constantly changing, high-pressure design that safety Dextor Clinkscale said "totally rattled" Theismann, caused problems for Redskins receivers, too.

"You've got to be dead-letter perfect, not only throwing the football, but the guys coming out of their moves have got to be so precise," Theismann said.

And Gibbs said that sometimes they were not.

"A couple things were busted on (Joe)," Gibbs said of receivers' routes that were not run properly. "The receiver adjustments that we'd like to have, we didn't get . . . It was a matter of our skill spots. We failed in our skill areas to make any plays or give us any real help there.

"Many times, you look at it and say it's always the quarterback . . . We had several things that hurt Joe on several key plays."

Specifically, he was talking about the two interceptions at the beginning of the second half. The first was by Everson Walls, covering Calvin Muhammad at the Washington 47.

"It wasn't a real sharp pattern outside for Joe," Gibbs said. "The ball was just a tad behind, and then they made a great play."

The series after running back George Rogers' fumble at the Redskins 40, Theismann again was intercepted, this time by Ron Fellows, covering tight end Don Warren, at the Redskins 43.

Another receiver, identity undisclosed, was supposed to run a fade route outside to clear some room for Warren. Instead, he went inside, clogging the middle with defenders, Gibbs said.

"It was more or less a bust. It was a receiver adjustment we'd liked to have had and didn't get," the coach said.

When receivers got one-on-one coverage, he added, they often failed to take advantage of it, a situation as aggravating as the Cowboys' success in several one-on-one situations of their own.

Perhaps the single most disturbing moment for the Redskins was Dallas' 55-yard touchdown pass from Danny White to Mike Renfro with six seconds remaining in the first half.

A respectable 10-7 deficit melted into a 17-7 margin, and a rout soon was to follow.

Renfro, who is not particularly fast, beat rookie nickel back Barry Wilburn on the play. Gibbs called it alternately "a catastrophic play" and "a very, very poor play."

It unraveled simply. With 38 seconds to play in the half, the Cowboys took over at the Dallas 39 after a punt. White threw six yards to Renfro on a short "out" pattern to the sideline and Wilburn made the tackle.

On second down, with the Redskins in a regular zone defense, Renfro made the same move and Wilburn went with him. Problem was, Renfro was running an "out and up," and slipped past Wilburn down field for the touchdown.

"It was the biggest mistake I could have made, jumping out like that," Wilburn said. "It was due to his experience and my lack of experience. I should have been aware of it coming."

Said Richie Petitbon, assistant head coach-defense: "He bit on the out. It was a rookie mistake, and I doubt it will happen again. Basically, what happened was he reacted as an athlete."

Gibbs said the fact Renfro does not have great speed helped him in his fake. "There's a tendency to crowd him. It was just a terrible mistake."

There were other issues. Gibbs was pleased with the pass protection given to Theismann by the offensive line, and said he would have used the unbalanced line (with right tackle Mark May moving to the left side) more if it hadn't been such a blowout.

He expects Rogers, who gained 47 yards in 13 carries, to get over his penchant for fumbling, which he has done four times in five games, preseason and regular season. It's likely Rogers will get more work in games as the season progresses, especially considering John Riggins' right hamstring strain, which will be "wait-and-see" situation this week, Gibbs said.

Meanwhile, Theismann, seemingly undaunted by his not-so-happy birthday Monday, said he was not embarrassed by the way he played.

"If you go out and try your best, I don't think you can be embarrassed," he said. "People want what we want. We want to win. Unfortunately, it doesn't always work out that way.

"If I took the game lightly and didn't prepare myself the way I think I can and made a fool of myself, I would say I'm embarrassed. People might say you made a fool out of yourself and threw five interceptions, but they're part of the game of football."

This Sunday, when the Redskins (0-1) play the Houston Oilers (1-0 after upsetting Miami, 26-23), Theismann expects he may find out what Washington fans think about his Dallas game.

"It always makes it interesting . . . when I set foot in RFK Stadium," he said. "They've tried to boo me out of this place for 12 years. I can tell you something. I'm still going to be there. I'll come regardless. You can bring your megaphones and bring your boos and bring your cheers. I'm still going to show up."