Notre Dame's 41-30 loss to Michigan dropped the Irish to No. 21 in the both the AP and coaches polls released Sunday morning.
Among future Irish opponents, Stanford held steady at No. 5/No. 4 while Oklahoma moved up two spots to No. 14 in the AP poll and No. 13 in the coaches poll. Attrition was about the only reason OU moved up -- first-year quarterback Trevor Knight completed 10 of 20 passes for 109 yards with two interceptions in an uninspiring offensive effort.
USC, which began the week at No. 25/No. 22, tumbled out of the rankings with a nails-on-a-chalkboard home loss to Washington State. Quarterbacks Cody Kessler and Max Wittek, despite having elite receivers in Marqise Lee and Nelson Agholor at their disposal, combined to complete 11 of 21 passes for 54 yards.
Washington State's lone touchdown came on an interception returned 70 yards into the end zone.
Elsewhere around Notre Dame's schedule, BYU rolled up 550 rushing yards against a hapless Texas defense in a 40-21 win. Michigan State's offensive struggles continued in a 21-6 win over South Florida -- two of the three Spartan touchdowns were scored by its defense.
Notre Dame's Week 3 opponent, Purdue, barely held off an FCS-level Indiana State team that allowed 73 points the week before, winning 20-14 in West Lafayette.