How 'bout that Bill Arnsparger. Guy shows up at Redskin Park Tuesday, watches his first practice Wednesday, and by Sunday the Redskins' defenders thought they were the '85 Bears. Sacks, interceptions, hurries, deflections. The worst defense in the NFL turned in a pretty impressive performance in beating the Arizona Cardinals.

The Cardinals did go 91 yards to score their only touchdown and temporarily put some drama in the affair. But you don't expect a defense to go from No. 31 in the league to perfect overnight. The Redskins would be quite satisfied with this improvement curve if it continues. Big Daddy Wilkinson and Dana Stubblefield were as dominating as a pair of defensive tackles can be, and Champ Bailey didn't look like anybody's rookie with those three interceptions.

On a night when Brad Johnson made several wonderful throws but also tossed his first two interceptions of the season, the defense finally acted like a full partner in this marriage. Whether Arnsparger actually made a significant difference is something that will take at least one film-study session to determine, and lots of forthright answers from the defensive coaches, which we're not likely to get.

Were the Redskins' defenders in better position than in the previous four games? If they were more certain of their assignments against the Cardinals, why was that the case? If it was simply better execution of the same old stuff, then why now all of a sudden? Why pick Sunday night to make the defensive plays they'd been unable to make the first four games? Maybe defensive coordinator Mike Nolan found some things in his own video studies that made a difference.

Regardless, the most foolish thing in the world is to try to make grand evaluations about a team after it beats the Cardinals. If you lose to them, shame on you. If you beat them, well, you were supposed to. After all, the Cardinals are only the most hopelessly forlorn, mismanaged team in the NFL, maybe in all of professional sports. It's a little easier to flex if your opponent is a mess, and the Cardinals are.

But if Sunday night marked the awakening of a Redskins defense, the victory here in the desert could have even more significance than a notch in the "W" column. Pretty offense is real nice. It provides lots of TV highlight material. But if you want to contend consistently, you'd better bring a defense. Ask Dan Fouts and those old San Diego Chargers who could never stop anybody when it counted. A team with a great offense and a dreadful defense is a house of cards. But when your defense can shut out the opposing running back, force turnovers, and put the quarterback on the sideline battered and bruised, then you could be onto something.

Sunday night, the No. 1 issue was the Redskins' defense. And it will be next week again down in Dallas. Sorry and no-account as the Cardinals are, it was still rather easy to see that the Redskins played defense like a contender ought to. Except for that 91-yard drive, the Redskins covered, smothered, hurried and sacked when players of their considerable talents are supposed to.

Start with the series that put the Redskins ahead, 10-3. On second down, Kenard Lang batted down a Jake Plummer pass at the line of scrimmage. On third down, Bailey made the interception and 59-yard return that broke a tie and put the Redskins ahead for good. Free points, as defenders like to say.

Next Cardinals series: Plummer tried one of those run-the-wrong-way- throw-across-your-body prayers. Bailey picked off that one, too.

To start the third quarter, Shawn Barber simply drilled Plummer on a blitz. Hit him so hard Plummer's right ring finger stuck in Barber's helmet.

Now, because Barber weighs 224 pounds, there has been some concern over what he can't do, like shed big tight ends and stuff the run. But let me tell you what Barber can do: run. He's quick, he's fast, and he can bury people. That ain't bad. Maybe the Redskins and Barber should look back at a guy who was built similarly to Barber--Wilber Marshall--and study the way he was used to wreak havoc.

Later in the second half, on a third-and-one play the Cardinals desperately needed to convert, Big Daddy just crushed Adrian Murrell for a two-yard loss which forced Arizona to cough up the ball.

After the Cardinals did score to make it 17-10, the defense smashed Murrell to the ground after a one-yard run. Big Daddy twirled backup quarterback Dave Brown around like a rag doll. And on third and nine, Stubblefield knocked down a pass. Once again Arizona had to punt, and the ballgame effectively ended.

A quarter earlier, the Cardinals' season might as well have ended when Plummer fractured the ring finger on his throwing hand.

In January after the Cardinals had thumped the Cowboys from the playoffs, Plummer looked just like what Bill Walsh had predicted: the next Joe Montana. Plummer could throw, Plummer could run, Plummer could throw on the run, Plummer was brash and daring, Plummer could make it up as he went. Like Brett Favre. But that was January, nine months ago. It's amazing what inept management, across-the-board fat-headedness, and 14 interceptions in six games can do to reduce a quarterback.

Plummer no longer looks like the next Montana; he's played this season like he ought to have been banished to a semi-pro team in Montana. It is difficult to tell who has had a tougher nine months, Plummer or Cardinals management. The muckety-mucks couldn't sign their key free agents, couldn't sign their rookies, couldn't do anything right the entire offseason to continue last winter's rare moment of success. Jake came into this season, apparently thought he was Montana, tried to carry the team all by himself and of course crashed under the weight of it all.

The Giants are in the Redskins' rear-view mirror already, as the Cardinals are now also. In a mediocre division, during a season in which everybody is about the same, a team with a great offense and an average defense can make some noise. The Cowboys in seven days will give all of us a better indication of whether the defense is ready to be dependable.