Maybe it was those long hours he spent jogging in the offseason.

"I spent that time telling myself I could be the best," safety Tony Peters of the Washington Redskins said. "I had gotten lackadaisical and I wanted to make a change."

Or maybe it was memories of his college days at Oklahoma, when the Sooners were unbeaten in three years.

"I thought about those days and I remembered how when one guy in the secondary would make an aggressive play, someone else wanted to make an even better play," Peters said. "It was catching, and we won, so it had to work. I saw myself as doing the same thing for the Redskins."

Whatever the reason, Tony Peters has become the catalyst of a Redskin defensive revival this season. As he has improved, so has a unit that gave up so many points and so many rushing yards last year that it couldn't be competitive with the NFL's elite teams.

This still is not a dominating defense. The Redskins rely, instead, on multiple formations, a mixture of blitzes and an ability to force turnovers and mistakes. And they rely on someone to provide a spark, someone like Tony Peters.

"Tony has the athletic ability to be a leader on the field, through the way he plays," said Richie Petitbon, the Redskins defensive coordinator. "When he starts hitting people, it's contagious. Everyone else sees it and they want to duplicate it. Look at last week."

Last week against Philadelphia, Peters had his best game as a Redskin and possibly the best in his eight-year career. Long before his game-clinching interception, he had set the tone for his teammates with a hard tackle of tight end John Spagnola that initiated perhaps the finest half a Washington defense has played in years.

"If Tony continues, he can be one of the best strong safeties in pro football," said Petitbon, who benched all-pro Ken Houston two years ago in what was a controversial decision and replaced him with Peters. "He's always had that ability, but he's never been consistent. He's taken vacations during games for a few plays or sometimes a quarter or a half . . . But so far (this season) he isn't doing that anymore.

"We're coming around as a unit, just in time for Dallas. We've stayed healthy and we've got a lot of flexibility. Now we will see how far we've come."

In Sunday's game, the Cowboys, as always, will provide a measure for the Washington defense and especially its improvement against the run. When the Redskins have limited Tony Dorsett to less than 100 yards, the games have been close. When he has run unchecked, Dallas has won easily.

At the same time, Dallas will provide a measure of Peters' skill. To alter their play against the run, the Redskins asked Peters and free safety Mark Murphy to be more aggressive and give faster support to the front four. So far, each has improved dramatically in both areas.

Washington has not allowed an opposing runner more than 100 yards or an opposing team more than 136 yards this season. Last season, when they ranked 21st in rushing defense, they allowed a league-high seven 100-yard games by individual rushers. Only one back this season has had a run of more than 20 yards against the Redskins.

"I always thought I played well, but I realized that I had reached a point in my career where I was comfortable," Peters said. "Subconsciously, I guess I really wasn't pushing myself hard enough.

"I wanted to change that. I wanted to be more consistent. I never tried to replace Ken Houston, because you can't do something like that, but I wanted to play better for Tony Peters and for this team. I knew I could give them more than I had. I had experience and I should be entering the peak years of my career. I didn't want to let them go by."

Of course, the defensive turnabout has been caused by more than just Peters' play. The defensive staff added new alignments during the offseason, including a permanent three-man front. Since 1979, the Redskins have shuffled players according to down and distance, but now there is more coordination behind those moves, which include as many as 18 players.

The coaches worked especially hard to shore up the Redskins' approach to second-and-long situations, in which opponents last season ran almost as frequently as they passed. Now rivals are throwing more on that down once again, allowing the Washington secondary more opportunities for interceptions.

Defensive line switches also have been successful. Tony McGee, acquired before the start of the season from New England for a late-round choice, has provided a consistent pass rush opposite Dexter Manley. Darryl Grant, in his first year as a defensive lineman, has been a pleasant surprise as a nose guard in the three-man line.

"If things continue like they have, the Tony McGee trade was very important," Petitbon said. "He gave us the extra pass rusher we needed and he's been a great leader. We now can get a rush without sending eight guys."

Likewise, lack of injuries and maturing of young players have helped.