DEFENSE GROWS UP QUICKLY YOUNG SQUAD REGROUPS IN 2ND HALF.

Byline: Steve Dilbeck Staff Writer

TEMPE, Ariz. - Such an unsightly beginning, such an impressive finish.

USC's defense, playing with just four returning starters from last year's national-championship team, appeared like a unit in serious trouble during the first half Saturday against ASU.

Sun Devil quarterback Sam Keller was having his way. Receiver Derek Hagan was giving USC cornerback Justin Wyatt fits. ASU moved the ball with relative easy.

And the unbeaten Trojans trailed 21-3 at the half.

``A couple of things didn't go our way, but we just kept fighting,'' defensive end Lawrence Jackson said. ``It's easy to get down on yourself and say, `Man, they're scoring a lot of points.' ''

Or simply, Man, they're moving the ball.

But in the second half, the young defense looked all grown up.

Suddenly it made key plays. It forced punts. It came up with key turnovers. Pressured the quarterback.

And held ASU to seven second-half points.

``I know in the final analysis they won the game for us,'' tailback Reggie Bush said. ``They held them.''

While a streamlined USC offense began exerting its will, the defense continued to give it opportunities to rally.

USC intercepted Keller four times in the second half - one by Wyatt that led to a touchdown, and one on an odd volleyball-like tip by Hagan that went right into the arms of true freshman safety Kevin Ellison.

``We had some great momentum plays by the defense to give us the ball back,'' USC coach Pete Carroll said.

The defense weathered the Keller storm, regained its footing - regained control.

``There were a lot of 'uh-oh' moments right there, but we stayed calm,'' secondary coach Greg Burns said. ``Normally, you see players bickering, which we didn't do.

``To play a team that throws the ball, and control them is impressive.''

The Trojans still trailed 21-17 in the third quarter when ASU decided to go for a fourth-and-1 at its own 45.

Linebacker Oscar Lua - whose interception set up USC's only first-half points - stepped into the hole and flattened tailback Keegan Herring for no gain.

``I saw the line open up, the running back put his head down, and I just shot the gap,'' Lua said. ``That was a huge play.''

The second half became a sea of big defensive plays.

Cornerback John Walker had a pair of interceptions, his last one in the end zone in the final minutes to seal the victory.

``Everybody doubts the secondary and thinks they cannot do it,'' said running back LenDale White. ``I think they are one of the tops in the nation.''

Keller was sacked five times, the Trojans coming with consistent pressure by the fourth quarter.

``We got our swagger back at the end when they got tired,'' Jackson said.

Steve Dilbeck, [phone]

stephen.dilbeck(at)dailynews.com