The consolation for the Pac-12's last-place team is that after falling far behind, the Cougars rallied to keep things sort of close and give Arizona coach Sean Miller something to grumble about afterward.
"We fought hard in the second half," Washington State's Royce Woolridge said. "Had we come out with more energy in the first half I think it could've been a different game."
Better free throw shooting would have helped, too.
The Cougars (11-17, 2-13) made 14 of 28 from the line.
"We missed a lot of easy layups, we had some wide open looks at the perimeter and obviously free throws were difficult tonight," said Brock Motum, who led Washington State with 20 points but was just 5 of 11 from the foul line.
The 17-point victory left Arizona coach Sean Miller in no mood to lavish praise on his team, particularly because of the 12th-ranked Wildcats' dubious second-half effort on defense, something that's become a distressing pattern.
If not for Kevin Parrom's offense, and Washington State's lousy free throw shooting, Arizona 73-56 victory on Saturday would have been a whole lot closer. Parrom matched his career best with five 3 pointers - in six tries - scoring a season-high 19 points.
"I don't know where we would be in this game if Kevin didn't play the way he played," Miller said.
The senior entered the game shooting 26 percent from 3-point range in conference play and was just 2 of 12 in his previous six outings. But he had the touch from the start this time, opening two 3s and the Wildcats (23-4, 11-4 Pac-12) led all the way.
"I was happy the first one went in," he said, "because I don't remember the last time I made a 3."
Arizona was up by as many as 21 points early in the second half before the Cougars cut it to 11 late. It was that lull, which followed similar drop-offs in a litany of other contest, that perturbed the coach.
"The second half at Colorado, the second half at Utah, the second half against Cal, the second half against Stanford wasn't very good," Miller said. "So it's our team is having a hard time playing very, very hard for 40 minutes. The one thing that I know is we're not the most talented, prolific offensive team, so when we don't play over the top hard and together, it really shows up."
Mark Lyons, feeling a bit under the weather, added 14 points and freshman Kaleb Tarczewski had a career-best 12 for the Wildcats, who began the day tied with Oregon atop the Pac-12.
DaVonte Lacy added 10 points for Washington State, eight in the second half.
Shortly after Parrom's two 3s made it 6-0, the Cougars went exactly 10 minutes without a field goal, resulting in a 14-2 Arizona run that put the Wildcats up 20-7 on Solomon Hill's 15-footer with 8:45 left in the half.
Angelo Chol's 15-footer made it 26-12 with 5:24 to go in the half, then Tarczewski's three-point play with 32.6 seconds remaining put Arizona up 35-19 at the half.
Washington State shot 35 percent and committed eight turnovers in the first half. And the Cougars were just 5 of 11 from the foul line in the opeing 20 minutes.
The second half got off to a magnificent start for Arizona, then went downhill from there.
An 8-2 spurt put the Wildcats 42-21 on Lyons' layup with 16:47 left.
But the Cougars went on a 10-0 run to cut it to 43-31 when Brett Boese sank a 3 with 12:47 to play.
After an Arizona timeout, Parrom drove the baseline for a reverse layup to boost the lead to 45-31, ending a 4:23 scoreless drought for the Wildcats. Nick Johnson's two free throws made it 47-31, but Lacy's 3-pointer sliced the lead to 47-34, then he made a drive to the basket to cut it to 47-36 with 9:08 remaining. Lacy was fouled on the play but missed the free throw.
Washington State cut it to 11 two more times and Parrom responded with 3s on both occasions, the latter making it 55-41 with 6:26 left. Parrom's final 3 put Arizona up 58-42 with 5:50 to go.
Cougars coach Ken Bone lamented his team's slow start but at least liked the last 20 minutes.
"I think we were the more aggressive team (in the second half)," he said. "We attacked the rim. We made a few 3s, although we still didn't make our free throws."