The rest did him good, Billy Kilmer said. His knee was hurt first, then his back. "And I was not performing up to standards," he said. So George Allen talked to him about changing quarterbacks six weeks ago. "I wanted to do anything to help the team," Kilmer said. "Let Joe try."

For six weeks, Joe Theismann replaced Kilmer as the Washingon Redskins' starting quarterback. Though the Redskins won four of six games with Theismann and so stayed in contention for the playoffs, Allen, the coach, went back to Kilmer today when it meant the most.

Kilmer was magnificent. On a day when only football crazies and $200,000 quarterbacks should have been out in the angry cold. Kilmer completed 14 of 28 passes and led the Redskins to a 26-20 victory over St. Louis. Once thought comatose, the offense under Kilmer produced its season high in points.

Afterward, Kilmer was a happy man. "I'm just grateful for the chance to come back and play," he said.

Did he feel vindicated by the performance?

"I don't think I had anything to vindicate." he said. "I'd been physically hurt, but all that cleared up two weeks ago. I've been throwing good, my legs are feeling good. I was ready."

But didn't the benching, the six weeks of watching Theismann work bolder him?

"That was nothing new." Kilmer said with a smile. "I've been benched before and then called back to win . . . "

A pause. A lowering of his eyes.

. . . the crucial game."

He didn't feel rusty because he'd been working so much in practice, Kilmer said, and he didn't feel any great pressure because his return to work had been a secret most of the week.

"Pressure is what you guys write about," Kilmer said to reporters. "And I didn't have you asking me about it all week. Oh. I know there's pressure. We had to win. But I didn't let it affect me."

The main worry, he said, was avoiding mistakes. "That's all I was a little apprehensive about, throwing interceptions," he said. "You wonder what's going to go on."

Pigskin pundits decided a couple of days ago that George Allen, by switching quarterbacks now, had left himself open for eternal second-guessing.

Did that matter to Kilmer?

"I was aware of all that," he said. "But I don't know whether he was taking a chance or not."

Kilmer didn't elaborate. He didn't need to. He'd already said more than he probably intended. In the delightful moments of victory Kilmer refused all opportunities to perform one of sport's most common feats: the self-congratulatory interview. Instead, he praised the offensive line for giving him so much time - he was sacked once, seldom hurried - and said. "I was only a part of a tremendous team effort. That's what we have to have to win anytime and we had it today."

But Kilmer's refusal to say I-told-you-we-had-the-wrong-quarterback does not diminish the truth that Allen, in switching, was not taking a chance. Theismann performs in the manner of a reckless rookie who will, some day, be a sensational quarterback. But not now. Not in a big game. For the games the Redskins must win. Kilmer ought to be the man and he showed why early in the fourth quarter.

This is the way Billy ran. Like an old man hobble-hopping across the street before a car ran over him. This is the way Billy ran with the football early in the fourth quarter. Like a creaking quarterback on second-hand legs. This is the way Billy ran when his team needed it the most. Like a winner.

It was third-and-11, only 42 yards away from a touchdown, when Kilmer thought to pass. The Redskins led 19-13. Back to pass, trying to produce what surely would be the decisive touchdown, Kilmer could find no receiver.

Everyone west of the Himalayas and east of Hackensack knows Billy Kilmer can not run. He's 38 years old, a time in his life when strenuous activity should be confined to the pursuits of pleasure, not a wild-hair run toward a homicidal linebacker.

But on third-and-11, Kilmer did the only thing open to him. He ran. This is the way Billy ran. Like it was a new invention he was trying out for the first time. "I was open and Billy started running," said Calvin Hill, the tailback, "but the way Billy runs, I couldn't tell if he was running for real or still going to pass."

"People do crazy things when they're scared," said Diron Talbert, the defensive tackle. And that's the way Billy ran, crazily, going 12 yards, sliding safely just in front of the first-down marker.

The linebacker, Tim Kearney, was so put off by the sight of Billy Kilmer running that he tried to put his elbow in the quarterback's left nostril. "He just grazed me." Kilmer said, eyes widening at the remembrance of tragedy averted.

But a personal foul was called anyway, moving the Redskins to the Cardinal 15-yard line. A short pass, a short run and Mike Thomas' beautiful run the last four yards produced a 26-13 lead.

"I didn't consider it a gamble," George Allen said. "Starting Billy was good coaching logic, good coaching sense. When you're starting a guy like Kilmer - well, he's one a lot of big games."