CORVALLIS, Ore. >> Finally winning at Reser Stadium after a long drought, the USC Trojans lifted interim coach Ed Orgeron to their shoulders in celebration.

Southern California defeated Oregon State 31-14 Friday night in Corvallis for the first time since 2004, and in the process became bowl eligible after a rocky start to the season.

Javorius Allen ran for 133 yards and three touchdowns and Marqise Lee returned from a knee injury and had five catches for 105 yards and a score for Southern California (6-3, 3-2 Pac-12. ) Cody Kessler threw for 247 yards and a touchdown and Silas Redd ran for 140 yards.

It was the third win in four games under Orgeron, who took over when the Trojans dismissed Lane Kiffin on Sept. 29 after opening the season 3-2.

“Great job of coming into a hostile environment and really never letting it affect us as much as it has in the past,” said Orgeron, who also took a turn conducting the USC marching band after the victory. “There was a belief in the locker room, at halftime, during the game.”

Oregon State’s Sean Mannion threw for 277 yards and a touchdown, but also threw three uncharacteristic interceptions in the loss, the second straight for the Beavers (6-3, 4-2) after a six-game winning streak.

Two of Mannion’s interceptions came in the red zone, and Oregon State had a field goal blocked and missed another.

“That’s too much,” coach Mike Riley said of the errors. “You’re not going to overcome that.”

Mannion, who went into the game leading the nation with an average of 408 yards passing, looked slightly off against the Trojans. He was sacked eight times last weekend in the Beavers’ 20-12 loss at home to No. 6 Stanford.

Mannion hit favorite target Brandin Cooks with a 43-yard pass on the opening series and the Beavers were helped by a pass interference call, but Trevor Romaine’s 46-yard field goal attempt was blocked.

The Trojans took over on the 29 and, on the first play from scrimmage, Kessler hit Lee with a 71-yard touchdown pass to put USC up 7-0.

Lee, last year’s Biletnikoff Award winner as the nation’s top receiver, was questionable going into the game because of a left knee injury that has sidelined him for two of the last three games.

The Trojans went up 14-0 on Allen’s 9-yard scoring run late in the first quarter.

Oregon State closed the gap with Mannion’s 27-yard touchdown pass to Cooks. On the next series, Ryan Murphy intercepted Kessler’s pass and ran back 41-yards to even it at 14 with 9:29 to go in the half.

Allen, a sophomore who had scored two touchdowns this season going into the game, put USC back on top with an 18-yard run and the Trojans led 21-14 at halftime.

Southern California opened the second half with Andre Heidari’s 34-yard field goal. Oregon State had a chance to pull closer, but Romaine’s 26-yard attempt went wide left.

Allen added a 52-yard touchdown run with 3:25 left in the third quarter to give USC a 31-14 lead for the final margin.

“That’s the way the game should be played,” USC linebacker Hayes Pullard said, “just being able to go out there, execute the plays and just have fun.”

The Trojans were coming off a 19-3 victory over Utah last Saturday.

Already depleted because of NCAA sanctions that have cost the team a significant number of scholarships, the Trojans have been stung this season with numerous injuries that have forced them to shift players and use walk-ons. Right tackle Kevin Graf (ankle), safety Su’a Cravens (groin), linebacker Morgan Breslin (hip), tight end Randall Telfer (knee) and cornerback Anthony Brown (knee) were among the players who did not play.

Oregon State was notably without senior receiver Kevin Cummings, who injured a wrist sometime during the first half of the loss to Stanford and required surgery. He could be back for a bowl game.

The Beavers also were hit on the opening kickoff when linebacker Joel Skotte collided with a USC player and lay still for several moments before he was helped off the field by trainers. Riley did not have a specific injury report but said Skotte was alert and talking.

The Beavers are known for their success against some very formidable Trojans teams. In 2008, the Beavers were 26-point underdogs when they knocked off then-No. 1 USC 27-21 on a Thursday night in Corvallis. Two years earlier, Oregon State topped then-No. 3 USC at Reser 33-31.

The two teams hadn’t met since 2010, when the Beavers downed then-No. 20 USC in Corvallis. Ryan Katz threw for 154 yards and two touchdowns while Jacquizz Rodgers rushed for 128 yards and another score in the 36-7 victory.

USC’s last win in Corvallis was a foggy 28-20 victory in the 2004 season when the Trojans went undefeated and beat Oklahoma in the Orange Bowl for the national championship — which was later vacated by the NCAA sanctions over improper player benefits.

“One of the main things we really focused on was that Oregon State beat our No. 1 team a couple of years ago,” Lee said. “We had a lot on the line here. Our main focus was to come out here and execute and that’s basically what we did.”