CORVALLIS — With a jump and reach for the ages, Oregon State defensive end Van Orsow deflected John David Booty’s two-point conversion pass to Dwayne Jarrett with seven seconds remaining to save a memorable 33-31 victory over third-ranked Southern California.

Moments later, thousands in the Reser Stadium crowd of 42,871 transformed the field into a frothing sea of orange as they celebrated with unbridled glee after Brandon Powers caught a desperation onside kick to seal OSU’s (5-3, 3-2) second victory over the Trojans (6-1, 4-1) in 38 years.

“How ’bout those Beavers!” shouted OSU coach Mike Riley as he weaved and bobbed through the ecstatic mob en route to the Valley Football Center.

A month ago, his job was in jeopardy after a dispiriting 13-7 home loss to Washington State left the Beavers 2-3 overall and 0-2 in the Pac-10. Now, after a three-game winning streak that has catapulted his team into bowl contention, he was on top of the world.

So was senior quarterback Matt Moore, insulted by some fellow students and booed by others in the crowd against WSU. He was 21 of 32 on Saturday for 262 yards and a touchdown, with no interceptions.

Many thought OSU needed a perfect game to defeat the Trojans, winners of 18 consecutive road games and 30-1 in their past 31 against OSU. Instead, the Beavers forced four turnovers and withstood the loss of its starting tailback and several key errors down the stretch to knock USC out of national-championship contention.

“I think we were ready for them,” senior tight end Joe Newton said. “I don’t think we were in awe of them, but obviously we respected them. They are a very good team.

“They had, who knows how many Pac-10 wins? We definitely respected them, but we knew we could play with them.”

OSU parlayed three Trojans fumbles and an interception into a 33-10 lead late in the third quarter before the Trojans came roaring back on two scores in a three-minute span encompassing the third and fourth quarters to get within 33-25.

They then drove 80 yards on 10 plays in 2:32 to draw within 33-31 on Booty’s 2-yard pass to Steve Smith with seven seconds remaining.

With the entire stadium in an uproar pleading for a stop, Van Orsow fought off a block, jumped and got his right hand on Booty’s low throw toward Jarrett, who was being covered by cornerback Coye Francies two yards deep in the end zone.

It bounced harmlessly to the turf.

“I saw Jeff tip it,” said linebacker Alan Darlin, who had seven tackles and a fumble recovery. “We knew we had the game, that there would be no overtime. It was just a great heads-up play.

“We knew we had to attack and finish, and that’s exactly what we did. We have to play with an attitude. The bottom line is, we’ve been having a ton of fun out there.”

Booty was 24 of 39 for 406 yards and three touchdowns; Smith had 11 receptions for 258 yards, breaking the old stadium record of 230 receiving yards set by Corvallis High graduate Robb Thomas against Akron in 1986. USC had 492 total yards and averaged 7.2 yards per play.

But it wasn’t enough. OSU’s efficient offense and reborn defense was the difference.

“Maybe early on we didn’t play up to our expectations. It was just a matter of this group jelling,” OSU defensive coordinator Mark Banker said. “Today we saw three tailbacks, six receivers and three tight ends who will all be drafted.

“They didn’t let that effect them. They believed in themselves as a group, bowed up and got the job done.”

And Beaver Nation, firmly back on the bandwagon after back-to-back road wins, roared throughout in approval in the most vocal show of support in quite some time.

“We love our fans and we love it when they love us too,” Darlin said. “We definitely felt the positive energy coming from the crowd. That was great and I hope it continues.”