The Vandals outrebounded the bigger Cougars 39-22, including 14-1 on the offensive glass.
"I felt the game was lost on the boards," Ernie Kent said after the loss. "There are some teams that are just really, really physical. And we've got to do a better job of controlling the boards - 16 second-chance points - was the difference in the game."
The Cougs, meanwhile, had zero second-chance points.
The Vandals weren't great from the field, they connected on just 25 of 57 shots (43.9%). But they were plenty good from beyond the arc. Idaho hit 9 of 16 from 3-point range against the Cougs (56.3 percent).
Josh Hawkinson led the Cougars with 16 points and 12 rebounds in WSU's first road game of the season. Ike Iroegbu and Conor Clifford both scored 12, Renard Suggs had 11, and Charles Callison recorded 10 points and seven assists.
Apart from Hawkinson, no Cougar had more than three rebounds.
--Hawkinson is now tied with James Donaldson for fifth all-time in double-doubles at WSU.
--Callison's seven assists were a career-high.
--Iroegbu was in double-figures for the sixth-straight game.
--Five Cougars scored in double-figures for the first time this season.
--WSU had eight blocked shots. Hawkinson and Izundu had three each.
--The Cougars play host to UTEP (6-2) Sunday at 3 p.m. in Beasley.