It was the culmination of the embarrassment, emblematic of the loss as a whole. Washington State center Aron Baynes slipped behind USC's defense, unnoticed, for a wide-open dunk. Then, with three Trojans standing by the baseline, the Cougars' Kyle Weaver somehow stole the in-bounds pass and dunked for a 14-point lead.
Minus their No. 2 offensive threat Davon Jefferson – benched for unspecified reasons – the Trojans struggled to score throughout the night. In the second half, their defense disintegrated.
A four-point halftime deficit turned into a 73-58 loss. No. 4 WSU's six second-half dunks and prolific 3-point output (10-of-19) made it that much more embarrassing.
Several minutes after both teams had cleared the floor and most of the 10,027 fans had departed, the Galen Center stereo began blasting the Traveling Wilbury's ominously titled: The End of the Line.
USC (9-6) has lost its first three Pac-10 games, and No. 5 UCLA awaits, following the Trojans' game with Washington on Saturday.
"We should be disappointed," freshman O.J. Mayo said. "We've just got to come together. The road doesn't get any easier."
Mayo led all scorers with 22 points on 9-of-17 shooting, but he struggled to find open space, scoring a few times in heavy traffic.
USC made 54.2 percent of its shots, and forwards Taj Gibson and Dwight Lewis combined for 32 points on 15-of-20 from the floor. But the Trojans could not match WSU's discipline.
The Cougars (14-0) doled out 17 assists, committed only seven turnovers and had six steals. USC had 11 assists, to 13 turnovers and no steals.
The Trojans reached the foul line twice.
"I do not remember them taking a bad shot," Floyd said of the Cougars, who were 25-of-53 from the field. "… I don't remember them making a pass when they didn't have two feet on the ground, two hands on the ball."
As Floyd had stated earlier in the week, Washington State – chock full of upper classmen – brought the same poised team to Los Angeles that it had last season. USC, relying on freshmen and sophomores, hung with the Cougars through the first half but never led in the final 20 minutes.
After containing WSU's inside game early, the Trojans allowed 22 points in the paint in the second half. They had allowed two in the first half.
"We didn't really communicate that much," said Gibson, who recorded the 100th blocked shot of his career. "A lot of driving kicks leading to open dunks. That hurt us in the second half.
"They were just real poised with the ball. Even if we locked it up, they would go down late in the shot clock until they got a good screen and got a good look."
Jefferson, who has scored in double figures in six of the past nine games, never took off his warmup jacket.
Floyd did not say if the freshman sat for disciplinary reasons, declining to elaborate beyond: "He didn't make the cut tonight. … It was a coach's decision. He's a young player. There's a lot of room for growth in Davon."
Floyd said that Jefferson, who did not start last week at Stanford, would return for Washington. Without him on Thursday, the Trojans had trouble making WSU pay when the Cougars collapsed on Mayo.
Asked if Jefferson's absence allowed WSU to focus more on him, Mayo said:
"It's not about me. I don't want it to be all about me. We've got a good team here, we've just got to pull it together."
Jonathan Kay can be reached at Jon@USCFootball.com