Clemson and Alabama remain atop the national rankings and should still be everybody’s favorite to meet in New Orleans on Jan. 13 to decide the national champion for the fourth time in five years. Let’s get that out of the way early.

But both teams have shown early signs of vulnerability. Alabama’s defense looked pedestrian by its lofty standards and it managed just 76 rushing yards against its first decent opponent on Saturday in a 47-23 win over South Carolina. Clemson’s Trevor Lawrence has already thrown more interceptions than he did all last year.

There are four schools that have displayed the potential to be serious threats thus far.

Ohio State

Ryan Day had never been a full-time head coach before. Justin Fields had never started a college game. The defense lost several difference-makers. There was reason to doubt Ohio State as a title contender. But after impressive blowouts of Cincinnati and Indiana, the Buckeyes look like the class of the Big Ten, and in addition to the impressive starts of Fields and Day, may feature the best defensive player in the country in defensive end Chase Young.

Oklahoma

As at Ohio State, the quarterback was a question mark. It clearly isn’t at the moment, with Alabama quarterback Jalen Hurts already amassing 1,253 total yards and 13 touchdowns. The defense, this program’s usual Achilles’ heel, has allowed a combined 28 points the last two weeks, though it has yet to be really tested.

Georgia

The team many predicted could upend the Clemson-Alabama championship monopoly has looked the part so far. The defense has allowed 23 points. The offense has scored 148. Of course, the Bulldogs have yet to face anyone of note, unless you count winless Vanderbilt. Notre Dame on Saturday evening in Athens will tell us a lot.

LSU

The Tigers own arguably the most impressive victory of the season, a road win at Big 12 contender Texas. Under new passing-game coordinator and former Saints assistant coach Joe Brady, quarterback Joe Burrow looks like a different player, already with 11 touchdown passes, 1,122 yards through the air and a completion percentage of 83.3. LSU is averaging 55 points per game, unheard of for the SEC school typically known for defense and running the ball. The young and talented defense, which did allow 530 yards of offense against Texas, will only get better as the year progresses.

ACC-trocious

The ACC produced a national champion last year and it has the No. 1 team in the country right now. But other than Clemson’s continued dominance, the conference is facing major issues. This weekend was the latest example of how weak it is after the Tigers.

Boston College was embarrassed by Big 12 doormat Kansas, losing 48-24, at home. N.C. State was manhandled, 44-27, by a West Virginia team that had just lost to mediocre Missouri. Virginia Tech needed to rally past FCS program Furman and Georgia Tech fell to The Citadel, another FCS foe.

Florida State, once the conference’s shining light, remains a shell of its former self under coach Willie Taggart, losing to Virginia after allowing 21 fourth-quarter points and committing five personal fouls in the final stanza.

Chip on Herm’s shoulder

The two head-coaching hires received far different reactions. One was hailed as a no-brainer, the other panned as a major mistake. Chip Kelly to UCLA was a perfect fit. Herm Edwards, the former Jets and Chiefs coach, at Arizona State wouldn’t work.

It’s still early, neither man having coached more than 16 games, but the returns so far are the opposite of those predictions. Kelly is 3-12 at UCLA and 0-3 this year. The Bruins have yet to score more than 14 points in a game this season.

Meanwhile, Arizona State picked up the Pac-12’s biggest win of the season thus far, upsetting Michigan State in East Lansing, 10-7, to improve to 3-0. Edwards guided the Sun Devils to a bowl game last year and is recruiting well, bringing in the Pac-12’s’s third-best class in 2019.

A lot of people — myself included — have been pretty wrong on these two hires.

Top 10

1. Clemson (2-0) (Last week: 1)

The Tigers committed two turnovers, converted just 5 of 14 third downs and still pounded Syracuse, which was supposed to be one of the ACC’s better teams, at the Carrier Dome, 41-6. The gulf between Clemson and the rest of the conference has never been larger.

2. Alabama (3-0) (2)

The Crimson Tide allowed 459 yards of offense and rushed for only 76. Forget the 47-23 victory over South Carolina. Nick Saban will treat this performance like a loss.

3. Georgia (3-0) (3)

Saturday against Notre Dame should provide real insight into the state of the Bulldogs, one of the nation’s most impressive teams so far.

4. Ohio State (3-0) (4)

As the other Big Ten contenders slip, either losing or barely avoiding upsets, the Buckeyes continue to roll, winning their three games by a 138-31 composite.

5. LSU (3-0) (5)

A flat start wasn’t unexpected after the emotional win at Texas. What mattered was the response, a thorough second half to put away Northwestern State.

6. Oklahoma (3-0) (6)

The Big 12 season now begins for Oklahoma and Jalen Hurts. He’s not going to miss the rugged SEC at all.

7. Auburn (3-0) (7)

After two walkovers, the challenges return for Auburn and Bo Nix. First is a trip to College Station on Saturday to face Texas A&M followed by another daunting road game at Florida two weeks later. There are few soft spots in the SEC.

8. Texas (2-1) (8)

There was no LSU hangover. Of course, the opponent — Texas punching-bag Rice — helped. The teams have met 43 times since 1966 and the Longhorns have lost just once.

9. Notre Dame (2-0) (9)

The Irish prepared for a trip to Georgia by mauling New Mexico, 66-14, at home. That’s like going from a third-grade quiz to the SATs.

10. Michigan (2-0) (10)

Jim Harbaugh has two weeks to figure it out, to get his team headed in the right direction, entering Saturday’s visit to Wisconsin. A win shuts everyone up. A loss and the noise increases.

Heisman Watch (in alphabetical order)

QB Joe Burrow, LSU

The opponent, Northwestern State, was weak, and Burrow didn’t slow down, completing 21 of 24 passes for 373 yards and two touchdowns.

QB Justin Fields, Ohio State

The road didn’t bother Fields, who threw for three touchdowns and ran for another in a rout of Indiana in his first game away from Ohio Stadium as a Buckeye.

QB Jalen Hurts, Oklahoma

His first touch was a 52-yard run, setting the tone for another dominant performance, this time a 439-yard, four-touchdown masterpiece against UCLA.

QB Trevor Lawrence, Clemson

The sophomore threw for 395 yards and two touchdowns in a blowout of Syracuse, but he has now thrown more interceptions (five) than he did all last year (four).

QB Tua Tagovailoa, Alabama

Tagovailoa is ahead of his torrid pace from last season through three games, having thrown for 12 touchdowns and 1,007 yards while completing a ridiculous 76.9 percent of his passes.