The box score will tell a large part of the story of Washington State's 87-80 win against Washington: UW committed 24 turnovers as a result of poor decision-making against WSU's zone throughout the game.
However, that explanation doesn't necessarily give adequate credit to WSU's defensive effort.
Despite Washington's 5-for-10 3-point shooting early in the first half, they never actually found a sustainable offensive rhythm against WSU's zone. And with WSU comfortably sitting in a zone, UW went 5-for-21 from beyond the arc the rest of the way, struggling to get anything going in the paint.
Those struggles in the paint included second-chance points in the second half: despite WSU losing the rebounding battle pretty badly overall, they did considerably better on the boards in the second half and even more importantly limited the Huskies to only three second-chance points in the second half and only two points in the paint. Huskies forward Matthew Bryan-Amaning was essentially a non-factor, finishing with six points on 1-for-8 shooting and struggling to adjust to WSU's defense consistently collapsing on him.
Considering that Cougars forward DeAngelo Casto was almost completely neutralized in the second half due to foul trouble, their defensive effort is even more remarkable.
So despite WSU fans storming the floor in celebration of what will be widely considered a major upset, the Cougars came out and played this game as the favorite with the Huskies looking like they were the ones who were simply overmatched.