The Pac-12’s top-4 all moved up in the rankings this week, with USC moving to No. 6, Utah to No. 12, Oregon settling in at No. 13 and Washington increasing 3 spots to No. 15. In the process, two also-rans who were off to great starts, Oregon State and Washington State, fell down a rung or two.

It’s clear that some of the conference’s top talent is about to separate itself from the pack.

But how much of that is fact and how much of it is fiction? Read below.

1. Impression: Caleb Williams looks shaken

Even in a 3-0 start with big wins over Rice, Stanford and Fresno State, there were times when USC quarterback Caleb Williams appeared frustrated with the offense. His tremendous production, though, masked the scarce off throw or poor read or head drop.

On Saturday in a 17-14 narrow win over Oregon State, Williams looked rattled from the get-go. He started the game 6-of-18 passing and only improved marginally from there, finishing 16-of-36. He was also facing pressure all night and often fought his way out of trouble with his legs, looking tired at times from all the fancy footwork.

Williams displayed true valor down the stretch, though, connecting with Jordan Addison for a 21-yard touchdown with 1 minute, 13 seconds left. In the face of a tough pass rush, Williams was poised and in control.

But he has to display better body language and not get so down on himself and the offense. That didn’t look great.

Verdict: First impression

2. Impression: Loss of Brant Kuithe will doom Utah

One of the things that separates Kyle Whittingham and the Utah Utes from the rest of the Pac-12 is their regular reliance on 2-tight end sets. Even when the Utes haven’t had noticeable talent at the position, Whittingham has favored going big overboard, rarely spreading the offense the way UCLA’s or USC’s does.

But with arguably 2 of the league’s top 4 tight ends in Brant Kuithe and Dalton Kincaid this year and last, Whittingham has had the horses to adjust the offense however he’s seen fit.

Well, now that luxury is gone with the loss of Kuithe to potentially season-ending knee injury. Kuithe, one of the top draft prospects at his position, is a 3-time all-conference second-team selection who was contending for first-team honors this year.

While Kincaid remains a top target and in fact starred against the Cardinal on Saturday, Kuithe’s absence robs Whittingham of the flexibility that he loves.

The Utes will survive, but the loss is a big one.

Verdict: False impression

3. Impression: A UCLA win over Washington puts it in the top 15

A convincing Week 4 road win over Colorado put UCLA at 4-0 for the first time since 2015, and the Bruins have won 7 straight dating to last year. The UCLA offense ranks 2nd in the conference in total yards and Dorian Thompson-Robinson and Zach Charbonnet looked great against the Buffaloes.

But in come the 15th-ranked Washington Huskies and their top-rated offense on Friday to the Rose Bowl for a classic marquee matchup. The Bruins improved pass defense will be put to the test by Michael Penix Jr. and Co., but the real matchup might be the play-calling battle between Chip Kelly and Huskies first-year mastermind Ryan Grubb.

If the Bruins can control the tempo against the well-paced Huskies — and if DTR takes care of the ball the way he has so far this season — UCLA could pull off the minor upset. The question is, if the Bruins do win, how much respect will they get? Maybe not enough to replace Washington in the top 15, but certainly a top-20 nod.

Verdict: False impression

4. Impression: Oregon’s road win at Washington State will go down as one of the best Pac-12 wins this year

Coming off of a high in Week 3 with a sound thrashing of the then-No. 12 BYU Cougars, Oregon could’ve been forgiven if it had found a way to lose in Pullman against an improved Washington State program.

And for a while, it looked like that was going to happen. The Cougars led for more than 50 minutes before the Ducks scored 22 points in the final 3 minutes, 48 seconds to snatch victory from the jaws of defeat.

The Oregon defense was far from perfect — Cougars quarterback Cam Ward passed for 375 yards and 2 touchdowns — but the Ducks stepped up when it mattered. In a hostile environment with everything on the line, Oregon’s Mase Funa intercepted a Ward pass with 1:01 left in the game and returned it for the game-sealing touchdown.

Embattled quarterback Bo Nix continued his redemption tour with a big day, passing for 428 yards and 3 touchdowns with 1 pick, throwing 2 late 4th-quarter scores.

That kind of clutch play lingers, and it will carry the Ducks for the next few weeks.

Verdict: First impression

5. Impression: Washington is the Pac-12 team to beat

USC looked pedestrian against Oregon State, Utah lost its best offensive weapon and Oregon needed a furious rally to beat Washington State.

All of a sudden, Washington, with its new head coach and new quarterback, is looking like the best team in the Pac-12. While the Huskies’ win over Michigan State looks less impressive by the week, Washington’s Saturday slashing of Stanford was a strong conference opener and put the Huskies at 4-0 heading into its Friday night matchup at UCLA.

Should Washington get by the Bruins unscathed, the next month lines up nicely, with games against Arizona State, Arizona and Cal. The Huskies could very well be 8-0 and in the top 10 before a tough November that includes road games at Oregon and Washington State and a home tilt with Oregon State.

Verdict: First impression

6. Impression: Cal is a threat after big win over Arizona

The Bears boasted the best individual rushing performance of the season in a 49-31 win over Arizona, with top recruit Jaydn Ott bouncing through holes and turning on the jets deep in the second level to the tune of 274 rushing yards.

How much of that was Ott and how much of that was the offensive line is up for debate. Not up for debate: How bad is Arizona’s run defense? Very bad.

So, no you probably can’t expect the Bears to be quite so dominant on the ground going forward. But it’s clear that Cal has a superstar in the backfield and a quarterback that isn’t losing games for the Bears. At 3-1 and with a big matchup with a hungry Washington State team, Cal has a big opportunity to head into a critical bye week on a nice roll.

Verdict: False impression