PULLMAN — When the students jump over the railings at Martin Stadium to mob the Washington State football team, something big has happened.

And that's what transpired Saturday.

The Cougars put together their most complete game of the season on offense and defense and thumped No. 16 Oregon 34-23 before a sellout crowd of 35,117.

It was the first Cougars victory over a ranked team since 2003 when WSU beat No. 5 Texas in the Holiday Bowl.

"A giant win," said a delighted Cougars coach Bill Doba.

The triumph improved the Cougars to 5-3 overall, 3-2 in the Pac-10, and moved them one victory from qualifying for a bowl game. Oregon fell to 5-2, 3-2.

On a day when several offensive and defensive players starred, the biggest scene-stealer was junior tight end Jed Collins, a converted running back and linebacker.

Collins caught an 8-yard touchdown pass from Alex Brink, scored on a 1-yard plunge when lined up in the backfield and made a tackle on a kickoff return.

Brink had a record day. He completed 20 of 23 passes — a school record of 87 percent — for 179 yards and two touchdowns. He was intercepted once.

"This is the biggest win for me," said Brink, a Eugene native who wasn't recruited by the Ducks.

Redshirt freshman Dwight Tardy became the first Cougars back to go over 100 yards as he gained 145 yards on 20 carries. He scored the Cougars' insurance touchdown.

The Cougars' most dramatic offensive improvement from recent weeks was in the red zone. In seven trips inside the 20-yard line in the previous two games, they had scored only two field goals.

On Saturday, they were 4 for 6 inside the 20 with the four scores all TDs.

"It wasn't a confidence issue," Brink said. "We weren't getting shut down in the red zone. We were shutting ourselves down."

The Cougars converted 7 of 13 third downs after going 0 for 11 in the previous week's 21-3 home loss to California.

The Cougars defense held the Ducks to a field goal through three quarters and contributed a touchdown when cornerback Tyron Brackenridge returned an interception 24 yards for a score and a 27-3 lead.

The defense forced four Ducks turnovers, chased Ducks starting quarterback Dennis Dixon in the third quarter by intercepting him on back-to-back possessions, and held star running back Jonathan Stewart to only 28 yards on 11 carries.

The Cougars defense lost starting tackles Aaron Johnson (elbow) and Ropati Pitoitua (knee) to injuries in the first quarter. Reserves Bryan Tarkington and Matt Eichelberger proved to be competent replacements.

The loss of the two starting tackles prompted the Cougars to use a lot of 3-4 defense, with sophomore linebacker Cory Evans inserted as the fourth linebacker. He made the third-quarter interception at the Cougars 14 that put Dixon on the bench.

Strong safety Eric Frampton made a career-high 16 tackles (nine solo).

One of the best Ducks performers was backup quarterback Brady Leaf, whose brother Ryan had a few big days himself in Martin Stadium and guided the Cougars in their 1997 Rose Bowl season.

Leaf entered the game with the Ducks trailing 27-3 and completed 16 of 27 passes for 262 yards and two fourth-quarter touchdowns of 4 and 36 yards to Jordan Kent, Oregon's three-sport star and son of Ducks basketball coach Ernie Kent.

The 4-yard TD cut the Cougars' lead to 27-16 with 7:37 to play. But Tardy put the Cougars safely ahead 34-16 with a 1-yard plunge with 1:57 left after a 68-yard drive during which he had a 46-yard run.

The final Ducks TD pass to Kent was in the final minute and completed a 20-point final quarter for the Oregon. It had started with a 6-yard fumble return for the touchdown by Ducks defensive end Darius Sanders.

The Cougars led at halftime 13-3 after two second-quarter TD passes by Brink. The first was the 8-yarder to Collins and the second was a 16-yarder to Jason Hill for his 31st career touchdown.

The conversion kick was blocked, and it took a tackle by kicker Loren Langley at the WSU 28 to prevent Oregon's Kwame Agyeman from scoring after he had taken a lateral from Jairus Byrd.

The first quarter lacked scoring but was memorable.

Ducks kicker Paul Martinez hit the crossbar in the first quarter on a 51-yard field-goal attempt. It appeared to some observers the ball had been spotted about 18 inches behind where it should have been, which could have made the kick successful.

The Cougars had a successful fake punt during which Scott Davis ran for a first down, but it was nullified by a delay-of-game penalty and punted to the 1-yard line.

Two plays later, Stewart fumbled but an offside penalty on Tarkington allowed the Ducks to keep the ball. No problem. On the next play, Dixon's fumble was recovered by Mkristo Bruce at the 10.

Two plays later, DeMaundray Woolridge fumbled at the 2-yard line for the Cougars and Blair Phillips recovered for the Ducks.

The problems didn't last and the Cougars got rolling and 2 ½ hours later everyone was smiling.

"If you could just see the faces of the guys in the locker room right now," Hill said to reporters in an interview room. "It was crazy down there."

Craig Smith: 206-464-8279 or csmith@seattletimes.com