USC to Be First Test for Arizona Defense : College football: The Wildcats are undefeated, but their opponents haven’t been as tough as the Trojans.

The nation’s top-ranked defense and one of the most potent pass offenses meet here today. But be forewarned, football consumers:

One coach, USC’s John Robinson, says it might be a war of nerves, a game perhaps decided by a bounce of the ball in the final minutes.

However achieved, both USC (2-2 overall and 1-0 in the Pacific 10) and Arizona (4-0, 1-0) hope a victory today in Arizona Stadium will help them break away early in the Rose Bowl race, on an afternoon when USC quarterback Rob Johnson puts his 70.8% completion percentage against a team that is giving up 152 yards a game.

Said Robinson: “It’ll be a low-scoring game, two touchdowns might win it . . . and it’ll probably come down to which team has the most nerve.”

Close and low-scoring? Not a pleasant prospect for the Trojans right now, what with kicker Cole Ford sidelined because of a back problem.

On the other hand, maybe Arizona isn’t as impenetrable as early-season statistics show. After all, Arizona has beaten Texas El Paso, Pacific, Illinois and Oregon State, none of which looms as more than a blip on this season’s college football screen.

USC has lost to two quality teams, North Carolina and Penn State, and had Penn State hanging on at the end of a 21-20 thriller. The victories, over Houston and Washington State, were routs.

And in its last three games, USC has demonstrated a defense nearly as impressive as Arizona’s.

In fact, Dick Tomey, Arizona’s coach, says maybe too much is made of his defense and not enough of USC’s.

“They’ve given up three points in their last six quarters,” he said. “We haven’t played anyone as tough as they are.”

Robinson wants a jump on the Rose Bowl numbers today.

“We have three home (conference) games remaining and four road games,” he said.

“We have to win all three at home and three out of four on the road. If you lose this one, you have to win the last three on the road.”

Whereas USC goes into this one with a surprisingly productive pass offense and a so-so running game, Arizona’s offense is still in low gear. In its 16-14 victory at Illinois, the defense did the scoring.

Operating with a sophomore quarterback, Dan White, Arizona’s offense has lost the ball nine times on fumbles and White has thrown four interceptions.

“You look at the kind of turnovers they’ve had and you get the feeling they might shoot the next guy who turns it over,” Robinson said.

Said Tomey: “We are a mess in that area. We turned it over six times at Illinois and had 13 penalties and still won. When we play the good teams in this league, we can’t do that.”

USC’s Johnson threw for a school-record 392 yards in last Saturday’s 34-3 rout of Washington State. He completed 21 of 26 passes, three for touchdowns. One scoring pass was to Johnnie Morton, who set another school record with 229 receiving yards.

“Johnson and Morton are doing things that jump off the film at you,” Tomey said. “I don’t think anyone can shut them down, but we’re going to try to keep them out of the end zone.”

Johnson, if he were to continue his present production to the end of the season, would pass for something like 3,400 yards. Rodney Peete holds the school record of 2,812 yards.

Robinson would like to set up his Johnson and Morton Show by establishing a run offense early, but he isn’t optimistic.

His three young tailbacks--David Dotson, Scott Fields and Shawn Walters--haven’t frightened anyone yet, and the Wildcats defend strongly against the run. Their four opponents have averaged minus 4.3 yards rushing.

“If Rob has to pass 40 times, we will lose,” Robinson said.

Then there’s USC’s defense. Tomey said before the season started that if the Pac-10 had a draft, his first pick would be USC defensive end Willie McGinest.

McGinest, 6 feet 6 and 245 pounds, knocked down four Washington State passes last week, and had five tackles, including a sack. He had a career-high 15 tackles in the previous game, at Penn State.

With Ford sidelined--Robinson said he might sit out another two weeks--USC’s kicker will be strong safety Mike Salmon, who had field goals of 36 and 38 yards against Washington State.