The Pac-12’s first 2 ranked underdogs fell behind early and could never crawl back.

Then No. 21 Washington State blew past No. 14 Oregon State in the afternoon, and the little guy took one home.

No. 19 Colorado and No. 22 UCLA have some major questions to answer, and pollsters might not wait around to see if they answer them.

Next week should continue to separate the contenders from the pretenders, but for now, here’s one thing I learned about every Pac-12 team in Week 4 …

Arizona: Noah Fifita steps in when it counts

You never want to need a good backup, but it’s always great to have one. And Arizona has one. Maybe the best in the Pac-12

Noah Fifita was only needed for 2 drives, but they were the defining drives. Fifita relieved an injured Jayden de Laura midway through the 4th quarter with the Wildcats trailing lowly Stanford 17-14 and promptly led the Cats in the eventual game-winning scoring drive. Then, after the Cardinal cut it to 1 with a Joshua Karty field goal, Fifita completed 2 key passes on the game-sealing drive, which allowed Arizona to play out the clock.

Should de Laura miss some time, the Cats are in a good spot with Fifita.

Arizona State: RB Cameron Skattebo puts Trojans’ defense on ‘skattes’

After 2 impressive years in Troy Taylor’s offense at Sacramento State, Skattebo took his talents to the desert and showed some glimpses of his 1,300-yard form from a year ago.

He had 173 combined yards and 2 scores in ASU’s first 2 games, but managed just 5 carries for 25 yards in the Sun Devils’ 29-0 debacle against Fresno State last weekend.

He bounced back in a big way against USC in a 42-28 loss Saturday night, totaling 190 yards and 2 touchdowns, 1 through the air and 1 on the ground. He did most of his damage in the running game, gaining 111 yards on 20 carries.

Cal: Normally reliable running game labors against Huskies

While its offense hasn’t exactly been clicking on all cylinders, the ground game has been effective under both Jaydn Ott and Isaiah Ifanse.

Both were bottled up by Washington on Saturday night.

Ott managed just 40 yards on 16 carries while Ifanse had 6 rushes for 30 yards, matching Ashton Stredick.

Colorado: Buffaloes hamstrung by bad offensive line

Entering Saturday’s matchup at always rocking Autzen Stadium, Colorado did what it could to replicate the chaos the Buffaloes would encounter. The coaches brought in sound machines and tried to replicate Oregon’s breakneck offense.

But the Buffs could do little about an offensive line that couldn’t stop a pack of nipping puppies.

After allowing 15 sacks in their first 3 games, Colorado allowed 7 Shedeur Sanders takedowns against the Ducks, along with several more pressures.

Oregon: Ducks’ 3-headed monster takes a blow

One of the things that makes the Ducks so dangerous is a running back rotation that is the envy of most if not all teams in the country.

Now their bountiful depth took a big hit. Noah Whittington, the perfect complement to Bucky Irving and Jordan James, suffered a lower leg injury that could sideline him for weeks.

With Stanford and then a bye before the season’s biggest showdown at Washington on Oct. 14, he has a chance to be back when it counts. If not, Bucky better ball out.

Oregon State: Lack of 3rd option kills Beavers

Prior to Saturday, the Beavers’ less-than-explosive passing game hadn’t held them back even a little.

But in a near-comeback against Washington State, Oregon State’s last of a tertiary option doomed it when it mattered. The Beavers still have not had a 3rd receiver account for more than 50 receiving yards this year.

Against the Cougars, Silas Bolden had 76 yards and Anthony Gould had 61 and no other Beaver receiver had more than 19 yards.

Stanford: Another baby back takes over for Cardinal

While his father, Sedrick Irvin Sr., didn’t have the career of another famous Stanford father — one Emmitt Smith — Junior won the head-to-head dual on Saturday, and maybe seized the starting role in the process.

While EJ Smith had just 1 carry for 0 yards, Irvin Jr. had 10 carries for 66 yards, including a 45-yard touchdown run. With Casey Filkins sidelined, Irvin picked up a starring role he may not give up.

UCLA: Running game falters against mighty Utes

The question after 3 games this year was not just who was UCLA’s starting quarterback, but who was the Bruins’ lead running back?

But after the 2-headed beast that is TJ Harden and Carson Steele we’re effective through 3 weeks, they were stuffed by the Utes.

Harden had 11 rushes for 31 yards and Steele had 11 for 29, both well below their season averages. With Dante Moore’s negative-51 rushing yards, the Bruins had just 9 yards on the day.

UCLA entered the game as the Pac-12’s leading rushing team at 270 yards per game.

USC: Trojans avoid Tempe tantrum

The joke going around Twitter was that USC was joining the Big Ten to escape playing at Arizona State, which has historically been unkind to the Trojans.

The Sun Devils played much tougher than expected, though, cutting the USC advantage to 7 midway through the 4th quarter, before Caleb Williams and Co. closed them out. Williams threw for 322 yards and 3 TDs — extending his season totals to 1,200 yards and 15 TDs, still without an interception.

ASU had won 3 of the past 6 meetings on its home turf.

Utah: Defense dominates in every facet

Despite missing a handful of starters, Utah was utterly dominant against the Bruins and true freshman starter Dante Moore.

Kyle Whittingham against a true frosh is always going to be a scary scenario, but you couldn’t have predicted 3-of-17 on 3rd downs, 7 sacks and a quick-pick-6 on the first play of the game.

Washington: Huskies a handful in all 3 phases

When you’re playing Michael Penix Jr. and arguably the best passing game on the planet, it’s not a good idea to stake them 2 quick scores.

Yet Edefuan Ulofoshio returned a Ben Finley pick 45 yards for a touchdown on Cal’s first drive of the game, followed by Rome Odunze housing a punt return on the Bears’ ensuing drive.

Before Cal could wake up, the Huskies scored on 5-of-6 possessions in the 1st half and put up 45 points in a 59-32 win that wasn’t actually that close.

Penix contributed 304 passing yards and 4 more TD passes, pushing his season totals to 1,636 and 16. He leads the country in both categories.

Washington State: Cameron Ward enters Heisman conversation

The biggest surprise from the Cougars’ thrilling 3-point win over Oregon State? Just how dominant Ward has become.

Off to a tremendous start this season, Ward firmly planted himself into the Heisman conversation with a 404-yard, 4-score performance against a fantastic OSU pass defense.

The Beavers had allowed just over 600 passing yards in their 3-0 start. Ward is up over 1,300 yards in 4 games, with 13 touchdowns and 0 picks. Heisman material.