AJ Armstrong shot a 6-under 65 to help Washington State make up a seven-shot deficit entering the final round to win the Itani Quality Homes Collegiate at Palouse Ridge Golf Course in Pullman.
The Cougars finished 33-under 819 and secured a one-stroke advantage over runner-up Boise State. Armstrong finished tied for fifth overall individually at 205.
Idaho placed ninth in the 11-team field at 13-over 865. The top Vandal was Adam Veenstra at 1-under 212, tied for 19th.
Alivia Brown shot 4-over 22 and placed tied for 25th and Washington State took 16th (40-over 904) out of the 18-team field in the Dick McGuire Invitational at The Championship Golf Course in Albuquerque, New Mexico.
Alexa Clark tied for eighth at 4-over 220 and Eastern Washington finished in sixth place out of the eight-team field (39-over 903) at the Battle at Old Works Invitational in Anaconda, Montana.
Subscribe to the sports newsletter
Get the day’s top sports headlines and breaking news delivered to your inbox by subscribing here.