SEATTLE -- In one wide-eyed moment, cutting through this hostile waterside swatch of football field like a fog horn, Matt Barkley was leading USC to another resounding victory.

The next minute, as if swallowed up by the gray chill, he was gone.

History will record Saturday’s 24-14 USC victory over the University of Washington at CenturyLink Field as a day when the Trojans’ ignored defense and forgotten running game showed up.

But the bigger story is how, and why, the quarterback disappeared.

It could have been an injury. It could have been fear of injury by his coach. It could have simply been the strangest game plan ever, sidelining three of the best offensive weapons in college football for more than half of a football game. Whatever it was, after the Trojans finally silenced the purple-throated passion that rocked the stadium for most of the night, they quickly left town after more strange and unsettled moments in a season full of them.

“My take on it is, it was terrible for our offense, with all the weapons we have,” said receiver Robert Woods afterward, his voice trailing as his eyes dropped.

It got “terrible” suddenly. One week after his best game this season, his form finally strong, his bearings finally set, Barkley was leading the Trojans toward midfield midway through the second quarter with a 17-7 lead. Then, as quick as you can wince, he was done. Barkley was thrown to the ground by linebacker Travis Feeney for an eight-yard sack, and nothing about him or the Trojans offense was ever the same.

At the time, Barkley had completed seven of 10 passes for 101 yards. After that moment, he was three for 10 for 66 yards, finishing with a season-low 167 yards passing.

How strange was it? Barkley didn’t even throw another pass in the first half. The Trojans ran on third-and-13. The Trojans ran on third-and-17. The first pass he threw, in the second half, was a tiny screen that was wide right, and the Trojans kept running, on third-and-10, on third-and six.

Woods, one of the toughest receivers in football, finished with five catches. Marqise Lee, possibly the most difficult receiver to cover in the nation, finished with two catches. After that sack, the Trojans did not score an offensive touchdown for the rest of the game against a team that last week allowed Oregon to score 52 points.

The strategy could have easily led to their defeat, and could certainly lead to future defeats as their schedule toughens. The Trojans were saved only by 227 yards rushing, a defense that recovered two fumbles and picked off two passes, and a special teams unit that blocked a punt for a touchdown.

The game ended, and things got even stranger. For the first time this season, the face of the Trojans for the last four years was not the face of the Trojans. Barkley was not one of the featured players holding a news conference in front of the USC banner, instead answering questions off to the side, in front of a bare wall in the bowels of the stadium.

I asked if he was frustrated. He looked up from beneath his black USC baseball cap, tightened his jaw, and answered, “Yeah,” before quickly clarifying that answer.

“Obviously, I want to pass the ball, but I’m happy with the win,” he said. “It was not a glamorous win, but our ground game was here, our defense was on fire, it was a team win.”

OK, first things first. Were you hurt on the sack, and is that why Coach Lane Kiffin rarely allowed you to pass again?

Barkley said he felt fine and added, “That had nothing to do with it.”

In his earlier news conference, Kiffin said, “There’s nothing wrong, and if there was, I wouldn’t tell you.”

So if Barkley wasn’t hurt, then why did Kiffin deflate the ball and the offense and quite possibly the team?

“Yeah, we played conservative once we got a lead like that, but we said it all along, it’s not about anybody’s numbers, or Heisman, or anything like that,” said Kiffin.” It was about the best thing to win the game.”

Kiffin noted they wanted to run the ball and avoid mistakes in this loud and unfriendly atmosphere, but why would that include running even on third-and-long situations?

“There were a few really long situations on third down, and the last thing I wanted to do in this environment was sit there and drop back and let these guys rush us and let the quarterback get hit,” Kiffin said. “Going back to that Stanford game ... there’s some times that I was getting Matt hit in those same situations and I made sure I didn’t do that today.”

When Barkley was informed of Kiffin’s words, it was his turn to wince.

“I’ve never heard that from him,” he said, the surprise showing clearly in his voice. “I can take any hit. That’s surprising.”

Just another one in a season full of them.

bill.plaschke@latimes.com

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