CORVALLIS —

Oregon State’s defense could only handle so much Thursday.

On a night when the Beaver defense covered up the deficiencies of a sputtering offense, it finally buckled down the stretch of a 29-23 double-overtime loss to Utah.

As the Utes poured onto the field to celebrate, the sullen looks on the faces of the Beavers was unmistakable: Oregon State had let another crucial Pac-12 Conference game slip away, this time against a ranked Utah team that looked so beatable.

“I think this is another game that is a good indicator of how competitive this conference is,” said OSU coach Mike Riley.

Blame an impotent offense. Blame the coaching. Whatever.

The Pac-12 is competitive, but most troubling is that the Beavers keep falling short against the league’s better teams.

The game was won when Utah’s Devontae Booker — who rushed for 229 yards on 32 carries despite being bottled up well into the fourth quarter — barreled through the middle of the exhausted Beaver defensive line for a 19-yard game-winning touchdown run that seemed too easy.

But really, the breaking point came earlier.

Oregon State’s defense made play after play, forcing two turnovers and holding Utah to 171 yards of total offense until late in the fourth quarter. Then Booker broke through on a 52-yard, third-down run — the first time all night Utah converted a third down — that set up his eventual go-ahead score, 16-13, with 4:06 to play.

OSU’s offense, which managed 391 yards of offense, fought back with a game-tying drive at the end of regulation and a fourth-down score in the first overtime.

But it was too late for the defense, which allowed Booker to score on easy romps in both extra periods.

Really, though, the offense put the Beavers defense in that position with its own inconsistency.

The offense looked awful much of the night, and quarterback Sean Mannion — who completed 21 of 37 for 272 yards and two touchdowns — and his receivers appeared completely out of sync for huge swaths of the game despite the respectable numbers.

Little worked for the OSU offense early, rolling up just 198 yards of total offense in the game’s first three quarters.

“Offensively, we can’t shoot ourselves in the foot,” Mannion said. “We have to be better on third down and when we get in the red zone.”

Thursday’s performance was hardly what OSU had hoped for from their senior quarterback playing what could be a pivotal Pac-12 Conference game.

Mannion did show off his talent when he reared back and lofted a perfectly thrown ball over two defenders to freshman Jordan Villamin, who streaked down the left sideline for a 72-yard touchdown that gave OSU a 13-9 lead with 13:49 to play.

But before that play Mannion was 10 for 22 for 118 yards and an interception, and 52 yards of that total came on one throw to Victor Bolden.

He looked shaky and unsure, like the freshman starter he was four years ago. Far from what the Beavers were looking for in their soon-to-be-in-the-NFL quarterback playing in a telling game that proved OSU is more pretender than an actual top-tier Pac-12 contender.

Case in point. After connecting with Bolden on that long pass play, which put Mannion ahead of USC’s Carson Palmer for second all-time in the Pac-12 in career passing yards, the quarterback overthrew Terron Ward streaking for what seemed like a sure touchdown.

Such inconsistency seems to be a troubling trend for Mannion, who outside of last year’s near-upset of Oregon in the Civil War, has played some of his worst football against the Pac-12 Conference’s best teams.

He has tossed 14 interceptions and just eight touchdowns in conference games since the Beavers were dominated by USC in November 2013.

Yes, Mannion engineered one last drive at the end of regulation to set up Trevor Romaine’s 50-yard field goal that tied the game at 16. But mostly, he did not play well enough.

To beat Utah “every facet of our game had to be at a top level,” Riley said.

Perhaps. But the offense failed to rise to the occasion, and now the Beavers stand perilously close to another mediocre season.

At 1-2 in the Pac-12 and 4-2 overall, OSU stands without a distinguishing win and a couple of notable losses.

Oregon State has been here before. In fact, they were here just last year after a fast start that ended with the Beavers losing every game against a decent team down the stretch.

It appears history is repeating itself. And that is not what anyone in Corvallis wants to see.

—Reporter: 541-617-7868; zhall@bendbulletin.com.