PULLMAN, Wash. (AP) — Shortly after the sun disappears behind the rolling hills of the Palouse on Friday night, Washington State will get the rare opportunity to prove its validity on a national stage. The opponent is No. 5 Southern California in an early Pac-12 showdown. But for the 16th-ranked Cougars (4-0, 1-0 Pac-12) it's also history. It's been 25 years since Washington State beat a top-five team in the regular season, not since a snowy November day in 1992 when Drew Bledsoe led the Cougars past rival Washington.