Amid the boos and mistakes, the injuries, the frustrations and the general puzzlement of an easy victory turned upside down, one thing became clear late yesterday afternoon at RFK Stadium:

For one weekend at least, the Washington Redskins' decision last month that sent kicker Tony Zendejas to Houston was a fortuitous one.

Because Zendejas missed two fourth-quarter field goals, both well within his range, and because two second-half Oilers touchdowns were called back on penalties and a third was ruled to have been caught out of bounds, the Redskins held on by their sliding fingernails to win, 16-13.

The victory brings their record into balance at 1-1, just like Dallas', several Redskins mentioned, with Philadelphia up next at home on Sunday.

It was left to quarterback Joe Theismann, who stalked off the field in anger time and again in the second half, to breathe the collective sigh of relief for the 53,553 who watched a 16-0 lead fade almost into oblivion.

"Thank God we won," he said.

The theme was repeated over and over by a team that would take a win, any kind of win, after that 44-14 loss at Dallas last Monday night.

"There was nothing pretty about it," said Coach Joe Gibbs. "Somehow we got out of this short workweek with a victory. The win is all that is important."

For the Oilers, also 1-1 after their upset of Miami in the season opener, any one of several big plays they made potentially would have won the game. There was cornerback Steve Brown's 23-yard interception return for a touchdown that would have given Houston a 19-16 lead. It was nullified by a call of illegal use of hands on safety Keith Bostic.

It appeared the penalty came when Bostic ran into Theismann, of all people, near the goal line.

"Good," Theismann said. "If that's the way I contributed, fine."

Theismann, who was intercepted five times by Dallas last week, fumbled twice and was intercepted once yesterday as he was tossed around in a sea of surprising Houston blitzes. He left the field to a crescendo of boos throughout the second half. But more on that later.

Soon after Brown's interception, Zendejas trotted out (he, too, to boos) for a 42-yard field goal. He missed it, wide left. With 14:55 to play, Washington still led, 16-13.

Back to Houston's what-ifs. On the Oilers' next possession, quarterback Warren Moon threw 51 yards to Drew Hill to the Washington nine. The call: holding on offensive tackle Eric Moran.

Then, two more, in heart-breaking succession for Houston. Moon completed an 11-yard pass to Tim Smith in the end zone with 4:22 to play. The call was an illegal shift by running back Mike Rozier.

Next play: Moon to Hill for a touchdown. Well, no. This time the officials ruled he wasn't in bounds, although replays indicated he may have been.

So, it was time for Zendejas again. When last we left him, he had failed to take Mark Moseley's job (although he did take $150,000 of owner Jack Kent Cooke's money in a guaranteed signing bonus) and was traded to the Oilers for a fifth-round draft choice.

It would appear Zendejas won't kick big field goals in Washington. With the Redskins or anyone else. His 33-yard attempt with 4:13 to play pounded into the right upright and fell back into the field. It was to be Houston's last chance to win.

"The ones I missed today were kind of depressing," Zendejas said. "I don't think there was any extra pressure kicking against the Redskins. Every game is pressure and every field goal is pressure. Sometimes, they just don't go in."

The Redskins were not ones to gloat, perhaps because Moseley's blocked extra point after George Rogers' 31-yard touchdown run in a furious first quarter made a 16-16 tie possible.

"I told him to keep his head up," Moseley said.

Free safety Curtis Jordan was more blunt.

"I'm glad we got Moseley and they got him," he said.

Houston Coach Hugh Campbell said all the missed opportunities were "frustrating," but added, "I know the call on Smith (Rozier's illegal shift) was right. Our line did get set after the motion. People told me the TV showed the other plays were incorrect. I do know for sure that Drew Hill caught his in bounds because I was right exactly on the line when he dragged his foot, and that was clear."

For all the chaos of the Redskins' second half, there was perfection in most of the first. Working with three tight ends ("a great approach," Gibbs said), they tore down the field. Starting running back John Riggins handed off on a reverse to Art Monk for a gain of 16, then Riggins went for three, five, then three again after a 22-yard pass from Theismann to Gary Clark, who breezed around two defenders.

On the sixth play of the 66-yard drive, there was a touchdown: an overhead grab by Calvin Muhammad of a 17-yard pass.

"You could see us pop there in the initial drive," said Gibbs. "I'm thinking, 'Here we go. We're rolling.' "

And so it was the next time they touched the ball, too. Riggins ran so much it almost got boring. Almost. He gained 48 yards in a 90-yard drive, but all he really was doing was setting up tag-team partner Rogers, whose leg-churning, I'm-not-stopping, 31-yard run into a crowd, then out of it, gave the Redskins their final touchdown at 4:23 of the first quarter.

Both were on their way to fine days before injuries sent them off the field. Riggins gained 84 yards and loads of attention when he didn't return right away after Rogers went out with a sprained back in the fourth quarter.

Riggins, who gained 84 yards in 16 carries, said he now has two sore hamstrings.

"It seems I am falling apart piece by piece," he said. "I pulled the right one in Dallas and today, the left one hurt. I don't think it's severe . . . Straight ahead is okay for me, but pivoting is tough."

Rogers, who gained 78 yards in 15 carries, said he will be "sore" for two or three days, but will play next week.

Riggins said he expects his injury to be "a day-to-day thing."

Gibbs was asked what he thought of it. "It's bothering us because it's bothering John."

After Moseley's 34-yard field goal midway through the second quarter, the Redskins led, 16-0. Then something happened, something that might faintly remind you of Dallas last week: the big play at the end of the half.

Theismann, blind-sided by blitzing free safety Rod Kush, fumbled, and Houston recovered on the Redskins' 32 with less than a minute to play. It was one of three times Kush got to Theismann yesterday -- the others resulted in another fumble and a nine-yard sack.

"They surprised Joe with it," Gibbs said.

With five seconds to play in the half, Moon threw two yards to Hill for a touchdown to make the score 16-10 (Zendejas earlier had kicked a 44-yard field goal, and added a 35-yarder in the third quarter).

"Those things are killers right before the half," Gibbs said, remembering the 55-yard touchdown pass to Mike Renfro the Redskins gave up last week. "They are absolutely emotional breakers for us."

The break complete, the second half was a tantalizing standoff in which the Redskins never threatened. "A real grinding type of game," Gibbs said. But he was smiling as he said it, just happy to win his first game of 1985.

The Redskins figure they should have won this game easily.

"This is the kind of team to beat by about 30-0," Jordan said. "But everybody will forget the score by next week anyway."