Mike Riley and his Oregon State Beavers move up big in the ranking after their win at UCLA. (US Presswire)

Here's CBSSports.com Rapid Reports Pac-12 power ranking:

We had some tough decisions to make in the middle and at the bottom of the weekly rankings. Oregon, though, stays at the top after a mammoth win over Arizona.

1. No. 2 Oregon (4-0): It's hard to say a 49-0 win over a ranked team is not as good as it looks, but that'd be splitting hairs. The Ducks moved up to No. 2 for a reason -- and that's because the defense is starting to look as good as advertised. Chip Kelly and Co. maintained the Oregon defense was better than its been in years, but two quick-pick-sixes and keeping the high-powered Wildcats offense out of the end zone? Fine, you got us. Last week's ranking: 1. Next up: at Washinigton State, Saturday, 10 p.m. (ESPN2)

2. No. 8 Stanford (3-0): The Cardinal rested up for their big Thursday showdown in Seattle against the Huskies, but the honeymoon period still hasn't worn off after the team's upset of USC, that maybe shouldn't have been an upset in the first place. Stanford's nation-leading rush defense has us thinking that maybe it wasn't just Harbaugh and Luck and luck in the first place, either. Last week's ranking: 2. Next up: at Washington, Thursday, 9 p.m. ET (ESPN).

3. No. 13 USC (3-1): While Stanford was sleeping, USC was back on the hunt, trying to make up for a loss that might've knocked them out of the national title picture. Problem is, the Trojans weren't altogether overwhelming in a 27-9 win over Cal. Matt Barkley's Heisman chances took another hit with two more interceptions, and while the ground game finally got clicking (296 yards) and the defense shut the Bears down, the vaunted offense rates just 49th out of 120 teams in scoring. Last week's ranking: 3. Next up: at Utah, Thursday, Oct. 4, 9 p.m. ET (ESPN).

4. No. 18 Oregon State (2-0): OK, fine, so the Beavers are for real. The Week 2 win over Wisconsin, which turned out to be Oregon State's season opener, opened people's eyes. The Beavers delayed Round 2, a 27-20 win over UCLA that came after a bye week, now has people convinced. Oregon State moved up to No. 18 in the AP Poll and up two spots on our list, which might matter even more. Last week's ranking: 6. Next up: at Arizona, Saturday, 10 p.m. ET (Pac-12 Network).

5. UCLA (3-1): This was the first major dilemma, with the Bruins, Sun Devils and Wildcats all too close to call. UCLA is given the benefit of the doubt because, well, Oregon State looks pretty darn good, and because the offensive line was without two crucial veterans in Jeff Baca and Greg Capella. The Bruins should get back to their winning ways against Colorado, but if they don't do so in convincing fashion, they lose that benefit of the doubt. Last week's ranking: 5. Next up: at Colorado, Saturday, 6 p.m. ET (Pac-12 Network)

6. Arizona State (3-1): So goes Taylor Kelly, so goes the Sun Devils, apparently. The Arizona State starting quarterback had a rough day against Missouri in a Week 2 24-20 loss that included two interceptions. Against a good Utah defense, Kelly was expected to have another tough task. Three touchdowns and 326 yards later, that settles that. The Utes look worse on offense than expected, so the Sun Devils' rout still leaves them trailing UCLA here, albeit ever-so-slightly. Last week's ranking: 8. Next up: at Cal, Saturday, 4 p.m. ET (FX).

7. No. 22 Arizona (3-1): The space shuttle Endeavor wasn't the only thing that came back down to earth. So to did Rich Rodriguez and his Arizona offense. Matt Scott was frazzled, through the air and on the ground, and the Oregon defense crashed the Wildcats party in a big way, returning two interceptions for touchdowns. Even though Arizona had its chances early, the game got away from the Wildcats, and we can't justify leaving them higher after such a huge loss. Last week's ranking: 4. Next up: vs. Oregon State, Saturday, 10:30 p.m. ET (Pac-12 Network).

8. Utah (2-2): What happened to the clean, crisp, controlled Kyle Whittingham-coached Utes we know and love? In suffering perhaps its worst loss in its brief Pac-12 tenure, Utah seemingly could not do what it does best -- run the ball and stop the opposing offense. John White managed just 18 yards on 14 carries and, as detailed above, Taylor Kelly looked like Jim Kelly. But not the Super Bowl Jim Kelly, the really good kind. Last week's ranking: 7. Next up: vs. USC, Thursday, Oct. 4, 9 p.m. ET (ESPN).

9. Washington (2-1): After a hit-or-miss preseason that saw a loss to the good (LSU) and wins over the bad (San Diego State) and ugly (Portland State), it gets a whole lot more one-sided for the Huskies. A gauntlet appears the next five weeks, with successive matchups against Stanford, Oregon, USC, Arizona and Oregon State. By the end of it, the Huskies will either be in the Top 25 or fighting for their lives. Last week's ranking: 10. Next up: vs. Stanford, Thursday, 9 p.m. ET (ESPN).

10. Cal (1-3): The Bears managed to keep it to within a score (well, with a two-point conversion) heading into the fourth quarter against the Trojans, but the fact we're celebrating that is really all you need to know about Cal's recent history. The Bears season-opening loss to Nevada could come back to bite Jeff Tedford if his job relies on a bowl bid. Last week's ranking: 9. Next up: vs. Arizona State, Saturday, 4 p.m. ET (FX).

11. Colorado (1-3): The second major dilemma: Do we put Colorado ahead of Washington State, even though we still kinda think the Cougars are a better team? It might just come down to this: If we can inspire Jon Embree to dole out more vicious chest bumps, we'll do it what it takes. Last week's ranking: 12. Next up: vs. UCLA, Saturday, 6 p.m. ET (Pac-12 Network).

12. Washington State (2-2): The last thing we want to do is anger an actual pirate, but because Mike Leach is just figuratively a pirate, we can drop the Cougars to the cellar. Ultimately, Washington State will probably wrestle back the coveted No. 11 spot, but for now, it's back to Pullman. Sorry. Last week's ranking: 11. Next up: vs. Oregon , 10 p.m. ET (ESPN2).

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