"They played an inspired, energetic game," WSU coach Ken Bone said during a postgame radio interview. "We did not compete with them at all."
After junior point guard Reggie Moore hit a 3-pointer to help the Cougars (14-15 overall, 6-11 conference) build a 5-0 lead, the Bruins responded with an 11-0 run and never trailed again.
WSU particularly struggled to contain guard Lazeric Jones, who made 6 of 7 shots en route to 14 first-half points as the Bruins took a 38-19 lead into the intermission.
While the Cougars have struggled defensively this season -- college basketball statistical analyst Ken Pomeroy ranks them 200th nationally -- offense generally has not been an issue. But WSU had more turnovers (eight) than field goals (seven) in the first half.
"We did not bring any intensity at all," Bone said. "This is not the time of the year where you want to play like we did tonight. I'm pretty disappointed."
The Cougars, who might have to win its regular-season finale at 3 p.m. Saturday at last-place USC (6-24, 1-16) and in the first round of the Pac-12 tournament to avoid its first losing record since 2005-06, never developed any offensive consistency.
WSU, which produced its fewest points of the season, looked as lost offensively as it has during anytime since the direct aftermath of senior guard Faisal Aden's season-ending knee injury Jan. 26 at Arizona, where junior center Brock Motum received little help. That again was the case as he scored a team-high 18 points. None of his teammates had more than five points.
The Cougars shot just 35 percent from the field.
Coupled with a defense that suffered its greatest struggles since Oregon shot 71 percent in the conference opener and WSU fell behind by more than 30 points during the second half. The Bruins (17-13, 10-7) shot 58 percent from the field, including 11 of 16 on 3-pointers.
"They probably made more 3s tonight than they have in a game all year," Bone said.
UCLA was led by Jones' 18 points, while guard Tyler Lamb made four 3-pointers en route to 16 points as the Cougars fell to 1-7 in conference road games.
"The clock is ticking on us," Bone said. "Hopefully we can play a lot better."