All of this is immaterial to Utah if we don't win Saturday. USC becomes a prohibitive favorite to win the South if it wins Saturday (With easily the league's toughest schedule remaining, I would also say we're a solid favorite to finish fifth; if we're lucky, tied for fourth or even third outright). Yes, it will still be tied in the loss column with Arizona, but it owns the head-to-head there. (EDIT: I keep forgetting that ASU didn't lose to USC, and only has one league loss as a result. It's remaining league slate, however, is considerably tougher than USC's.) USC also doesn't play Oregon and will have gone 4-1 vs. South Division foes. As things stand, only Utah is undefeated vs. the South right now, but only at 1-0, and if it loses Saturday, can finish no better than 4-1 in the division, where USC would again have the tiebreaker.
Show me otherwise, but the only way Utah can win the South with a loss Saturday would be for USC to lose out to get to 5-4, with Utah finishing 6-3 or 7-2. With a closing league slate of UCLA, Cal and Wazzu, that's not happening.