Washington State’s 37-15 win at UCLA on Saturday reflected all that’s changed for its defense since last season.

The Cougars shut out the Bruins in the second half, after allowing 30 post-halftime points in a 44-41 overtime loss in October 2005.

They forced UCLA starter Patrick Cowan into a 17-of-37, two-interception performance after letting Drew Olson throw five touchdowns on their home field.

And most importantly, the Cougars allowed only 86 rushing yards after conceding 179 to Chris Markey and Maurice Jones-Drew, who earned the last one on the game-winning score.

“”Eleven heads to the ball,”” said senior defensive end Mkristo Bruce in a phone interview Tuesday. “”That’s been our overall theme, 11 heads to the football. And just have fun. Our other big goal is to party on the sideline, try and make big plays so we can boogie.””

Bruce admitted that being a Washington State defender in 2005 wasn’t much to celebrate.

Even though he tallied a career-high 10 sacks, the unit as a whole gave up 31.5 points per game, which helped lead to five of the team’s seven losses coming by four points or fewer.

Through nine games, the Cougars are allowing only 18.7 points per contest, giving some breathing room for an offense that’s scoring less in turn.

“”This year we’ve been working as a team, rather than one side working and the other side not,”” Bruce said. “”It’s beautiful to go out and try to bail each other out, if need may be.””

Washington State head coach Bill Doba said in a teleconference Tuesday that he believes his defense has made a complete turnaround.

He credited sterling leadership from senior linebacker Scott Davis and said the team’s depth at the position has led to a successful move to a 3-4 base defense that uses only three down linemen.

He said first-year starting cornerbacks Tyron Brackenridge and Don Turner have fit well in cover-two and cover-three pass coverage schemes that don’t force them into one-on-one situations, which expose their lack of experience and optimal physicality.

But most of all, like Bruce, Doba pointed out a widespread shift in attitude.

“”These guys are tight, I’m telling you,”” he said. “”I think Mkristo Bruce said that in an article I read after (Saturday’s) ball game. They want to do everything they can to help us win.””

UA head coach Mike Stoops said he’s most concerned about the potential of the Cougars’ pass rush.

Washington State leads the Pacific 10 Conference with 29 sacks this season, after topping the conference with 34 a year ago.

The team got nearly a quarter of its output on Sept. 23 with seven sacks against Stanford, which has allowed the second-most sacks in the nation this season.

Still, Stoops said, the Wildcats must at least be wary of Bruce, who leads the Cougars with 10 sacks, including a career-high five against the Cardinal.

“”They blitz you and come after you,”” Stoops said. “”They’ll come after us with pressure, and we have to make sure we’ll be able to protect our quarterback.””

If not, Bruce and his teammates just might get a few more reasons to party Saturday.

“”We’ve got a bunch of clowns on this team, so anytime there’s a big play, there’s high-fives, little dance moves on the sideline,”” he said. “”We just watch it play out and have fun.””

Washington State aims to be on a high after their domination of the Bruins, a victory that made the team eligible for their first bowl since 2003.

UA quarterback Willie Tuitama said he isn’t worried about dealing with the Cougars’ defensive momentum on the road.

“”We just had a bye (week), so we know that we’re rested,”” he said. “”We just have to go out there and play, not think about, ‘They beat them and them.’ It’s just another day.””