Sophomore R. Jay Soward's 95-yard kickoff return for a touchdown to open the second half was the third of his career and his second against Washington State.
It also puts him halfway to the USC record for kickoff returns for touchdowns in a career, the NCAA-record six by Anthony Davis.
Soward said he was eager to do something to change the momentum of a game USC trailed, 21-6, at halftime.
"We had no emotion at that point. I kind of blacked out at halftime, and I just came out and we said, 'Everybody, come on, let's make a play,' " he said. "I felt I had to make a play."
After the game, he was more intent on being unable to catch one of the final desperate passes.
"I haven't made a play yet," he said. "I haven't done anything to contribute.
"There is no fire out there. You know there's desire. You just can't feel any fire. You walk to the huddle, you walk out of the huddle. I do it myself. We're missing blocks, getting sacked, running for a one-yard loss."
Quarterback John Fox wasn't as smooth as in his debut, even though he passed for 229 yards.
"We're just not clicking on all cylinders," Fox said. "Too many penalties. . . . And I mixed some signs up and didn't get some correct plays. I've got to work on that."
This is the fifth time in 104 years of football that a USC team has opened a season 0-2. Before this, the only Trojan teams that began a season with two defeats were those of 1896, 1902, 1957 and 1960.
The 1960 team dropped three in a row, then won four of its next seven.
When he saw teammate Kevin McKenzie take off with a 51-yard touchdown pass for the winning points in Washington State's victory, senior defensive end Dorian Boose saw the Coliseum in a whole new light.
"There was, like, electricity," Boose said. "I mean it. On the horizon, I saw sparks. I'm not on drugs. I'm serious. I looked above the Coliseum and I saw sparks. It was, like, magic."
Cougar Coach Mike Price said, "This is great for the seniors, especially all the guys from California."
Forty-four Cougar players are Californians.