During the WAC and MWC days, this was always the case for BYU. Even when BYU had putrid teams during the last few years of Crowton's tenure, a win against BYU had teams rushing the field and acting like they had just won the Superbowl.
USC has always been the traditional big dog in Pac10/12 football, so even when they are down, everyone still uses them as the measuring stick of their own success. The same thing applies to UCLA basketball.