We're assuming Utah still plays BYU, right?
Here's every opponent for both teams, in order (FPI ranking):
# 12 Utah (BYU at home)
#18 UW (both, Utah on the road, BYU at home)
#22 USC (both, Utah on the road, BYU at home)
#24 WSU (Utah at home)
#34 Boise (BYU at home)
#35 Tennessee (BYU on the road)
#45 ASU (Utah at home)
#50 BYU (Utah on the road)
#55 UCLA (Utah at home)
#56 Cal (Utah on the road)
#64 OR ST (Utah on the road)
#68 USU (BYU on the road)
#91 USF (BYU on the road)
#95 Toledo (BYU on the road)
#101 Liberty (BYU at home)
#110 NIU (Utah at home)
Even if we assume Utah loses to USC at home (which is by no means a guarantee), Utah embarrassed WSU, who is ranked higher than any of BYU's wins. Utah's worst plausible record against BYU's schedule is 9-1, and with USC at home, 10-0 is pretty likely.