Michelle Plouffe led the Utes (10-14, 3-10) with 31 points and 11 rebounds, and Malia Nawahine had 14 points.
The Utes entered the game having lost their three previous, all of which were on the road. Being at home where they were 7-4 before Friday's game should have given them an edge, particularly since the Cougars were dealing with some struggles of their own, having lost six of their last seven games.
Losing a game they knew they should have won left the Utes looking like they'd been stood up on a Valentine date.
"It's hard," Plouffe said. "We thought we were going to get this one and it would be the one to get us rolling. We're running out of games here. It's tough, especially for a senior, it's not what I imagined."
The knife in the heart was a missed free throw by Washington State's Tia Presley that was rebounded by the Cougars. Lia Galdeira stepped back and drilled a 3-pointer, putting the Cougars up 73-65 with six minutes to go.
"It's hard right now," Utah coach Anthony Levretts said. "I don't have any answer right now. Night in and night out we are finding different ways to lose. Our kids are competing, but one night it's a big that beats us, another a wing and another a guard. We're just young."
The big difference Friday came at the free-throw line, where the Cougars were 26-of-35 and the Utes were just 10-of-14. What hurt the Utes the most is all of their misses came in the second half when they were trying to rally. But instead of cutting into Washington State's advantage, the Utes just dug themselves deeper in the hole.
Case in point came with 2:49 left and the Utes trailing 78-69. Plouffe drove to the basket for a layup and was fouled, but failed to make the free throw and Washington State got the rebound.
The Utes had no choice but to start fouling.
"I hate to use the cliche they wanted it more," Levretts said. "But there was a stretch where we turned it over and they outcompeted us."
The Utes continue their homestand on Sunday against Washington at 3 p.m.
With games against Arizona, ASU, USC and UCLA remaining following Sunday's contest, Utah's hopes of climbing up the standings from their 11th-place position before the Pac-12 tournament in Seattle seem dim, but they aren't giving up, Plouffe said.
"We still have some games left and we need to put together a run," she said.
Storylines • Utes drop 4th straight
O In short • Utes lose their fourth game in a row despite Michelle Plouffe's 31 points.
Key moment • Lia Galdeira's 3-pointer puts the Cougars up 73-65 with six minutes to go.
Key stat • Cougars make 26 of 35 at the line while the Utes make 10 of 14.