Oregon State is easily the biggest surprise in the Pac-12 Conference four weeks into the season.

The Beavers might have benefited from a lot of extra practice in the early going with their season opener against Nicholls State being postponed because a hurricane made travel unrealistic and a bye week.

Coach Mike Riley's team upset two ranked teams in Wisconsin and UCLA and now finds itself in the polls at No. 21 (USA Today coaches) and No. 18 (Associated Press). Riley points to improvement in the trenches as one major reason his team is off to such a good start.

But the Beaver defense is playing exceptionally well early on, especially on third downs. And that might be the biggest factor in what could be a huge one-year turnaround if it continues. The Beavers were 3-9 last season.

Opponents have converted just four times in 29 attempts on third downs against OSU in two games, which has helped Riley's team limit its first two opponents to 7 and 20 points, respectively.

"I think it's probably both fronts," Riley said. "That's probably the biggest difference I think. We're doing such a better job at this point with run defense and that puts us into a lot better third-down defensive categories. We're doing a great job on third down."

Riley had a young team last season. He said he has watched his players grow and learn and it's starting to pay off on game days. Colorado coach Jon Embree is hoping the same thing happens with his team in the next few years.

"I think it's confidence as much as anything," Riley said. "A lot of those guys played their first football last year and they got a taste of what it was like. And, of course, for us, it was hard last year. We didn't do very well."

Funny guy

USC coach Lane Kiffin banned a reporter from covering practices and a game a week ago after that reporter wrote about an injured player, violating Kiffin's policy. Kiffin then cut-short a post-practice session with reporters last week just 29 seconds in when a different reporter asked an injury related question.

Kiffin received just one question from the media Monday, leading to this quip when he was told there were no more questions.

"I like it," Kiffin said. "That's the second quickest press conference I've ever been a part of."

The one question Kiffin did answer concerned how the offensive line's struggles have affected the play of quarterback Matt Barkley, who has already thrown five interceptions.

"I think a lot," Kiffin said. "I think obviously in the Stanford game that showed up. You're getting hit and can't set your feet, that makes a difference with all quarterbacks."

Penalty prone

Don't be surprised to see flags flying around the field on Saturday when UCLA visits Folsom Field. The Bruins are the second most penalized team in the Pac-12 so far this season, averaging nearly nine flags per game for a league-worst 88 yards in losses each week. The Buffs have been flagged more than seven times per game.

Trouble brewing

California has allowed 17 sacks in its first four games. The only team worse at protecting the quarterback so far is Colorado, which has given up 18 sacks.

The Bears and Buffs face two of the top pass rushing teams in the Pac-12 this week. It might be worse for Cal against Arizona State, which leads the nation in tackles for loss.

"That's going to be key, and that's not just in the pass game," Cal coach Jeff Tedford said of the need to get the Sun Devils blocked. "It's also in the run game as well. The key is to get positive plays on first and second downs so we don't end up in a lot of third-and-extra-longs like we have in the past."

Quotable

CU coach Jon Embree admits he doesn't get a lot of chances to see other Pac-12 teams playing live on Saturdays, but he did watch Oregon beat up on Arizona during the flight home from Washington State last week.

"It looks like Oregon has gotten faster, which is disappointing," Embree said. "I don't know where Chip (Kelly) gets it, but obviously he's got them rolling."

Kyle's rankings

(Previous week's ranking and team's record in parentheses).

1. Oregon (1st/4-0, 1-0) -- The Ducks look very good, but let's remember all of their toughest tests come in the final seven games.

2. Stanford (2nd/3-0, 1-0) -- The Cardinal is the second least penalized team in the conference with the best turnover ratio at plus-six. That will win a lot of games.

3. USC (3rd/3-1, 1-1) -- The USC offense just hasn't been quite as dynamic as anticipated. The Trojans are seventh in the league in passing with all that talent at quarterback and wide receiver.

4. Arizona State (6th/3-1, 1-0) -- This is one of two teams in the league that has played three opponents from BCS conferences and it's the only defense allowing fewer than 300 total yards of offense per game.

5. Oregon State (8th/ 2-0, 1-0) -- Two games, two wins over ranked opponents. Tough to ignore the Beavers, but we're not completely sold on them just yet.

6. UCLA (4th/3-1, 0-1) -- The Bruins might have started believing what people were saying about them and forgot to prove it on the field last week. That's probably bad news for CU this week.

7. Washington (7th/2-1) -- The Huskies get their first opportunity to make some noise in the North Division hosting Stanford this week.

8. Arizona (5th/3-1, 0-1 ) -- The Wildcats were steamrolled by Oregon, showing too many folks prematurely put them in the top 25.

9. Utah (9th/ 2-2, 0-1) -- The Utes are mediocre right now and nothing close to the South Division contender some made them out to be in the preseason.

10. Cal (10th/1-3, 0-1) -- The Bears produced their best effort in years against USC last week but still came up well short. How long will this team continue to fight like it did against the Trojans?

11. Colorado (12th/1-3, 1-0) -- A nice step in the right direction for the Buffs last week, but fans should be prepared for more tough times ahead before victory celebrations become the norm again.

12. Washington State (11th/2-2, 0-1) -- The Cougars really want those last 7 minutes back against the Buffs. Back in familiar territory.

-- Kyle Ringo