Stanford took control of the Pac-12 North Division away from Oregon last week, but the Cardinal gave it back on Saturday.
The fourth-ranked Cardinal lost 20-17 at USC on Saturday night, possibly crippling Stanford's hopes of another BCS bowl. The Cardinal fell to 8-2 overall and 5-2 in the Pac-12 after its second loss to an unranked foe this season.
Meanwhile, Oregon defeated Utah 44-21 to move into sole possession of first place at 6-1. The Ducks will win the North if they defeat Arizona and Oregon State to wrap up the regular season.
While Oregon and Stanford are the only contenders left in the North, USC made the South a three-team race.
Arizona State defeated Oregon State to remain in first place at 6-1, but UCLA and USC both won to improve to 5-2. UCLA and Arizona State face off next week for first place while the Trojans are also in the mix with games against Colorado and UCLA remaining.
While the battle for the top spot in the conference is still up in the air, California likely clinched the title as worst team in the conference when it lost to Colorado in a battle of two teams that were winless in conference play.
FIVE BIGGEST TAKEAWAYS FROM WEEK 12 IN THE PAC-12:
1. Washington looks likely to go 7-5 for the fourth season in a row despite having higher hopes coming into the season. Washington is 6-4 and has to go to Oregon State before hosting Washington State to end the season.
2. Arizona State's visit to UCLA next week will likely determine the South Division champion. The Sun Devils are 6-1 and UCLA is 5-2, so the Sun Devils can clinch the title with a win and the Bruins can move into first place with the tiebreaker if it wins.
3. Washington State is better on the road than it is in Pullman. The Cougars almost won at Auburn in a nonconference game and have victories at USC, California, and Arizona while going 0-3 in conference home games.
4. Marcus Mariota may not be out of the Heisman Trophy race just yet. The Oregon quarterback was considered the favorite until he struggled in a loss against Stanford, but he bounced back to go 19-for-26 for 288 yards and three scores against Utah.
5. Stanford plays its best against its toughest opponents. The Cardinal have given Oregon its only loss in the last two seasons, but Stanford's losses during those years have been against unranked Washington, Utah, and USC.