Both played at the exact same timeslot (10:15pm ET) on the exact same channel (ESPN) in back to back weeks. In both matchups there was a top 15 team playing. Last week's BYU matchup garnered 1.5 Million viewers, and this week's Utah matchup garnered 907 thousand viewers. BYU outgained Utah's viewership by 40%!
You literally can't get any more perfect comparison than that (Week 5 vs Week 4 right below it)!