I wrote last week that No. 1 Alabama had separated itself from everyone else in the SEC, and I was criticized mightily for being too presumptuous.

Well, I'll admit it: I was wrong.

The Tide are not only head and shoulders above everybody in the SEC, they're better than any other team in the nation.

Yes, I'm including defending national champion Clemson, as well as Oklahoma and Penn State.

Alabama outgained Vanderbilt by 599 yards on Saturday. Jamie Gilliam/Icon Sportswire

Alabama is playing at such a high level, I don't think there's anyone in the SEC who could put up much of a fight against the Crimson Tide right now.

After demolishing Vanderbilt 59-0, ESPN's Football Power Index projects Alabama has a 68 percent chance to win the SEC, which is highest among Power 5 teams. FPI also projects that the Tide would be 11.4 points better than any other SEC team on a neutral field, which is the highest gap between the league's No. 1 and No. 2 teams through at least this point of the season since 2008, when Florida won its second national title with Tim Tebow.

Now, I'm not saying Alabama will win its fifth national championship in nine seasons. Last season, it was probably the best team, but Clemson had the best player in quarterback Deshaun Watson, who threw the winning touchdown with one second left in a 35-31 win over Alabama in the title game. But the Tide remain the benchmark by which all contenders will be judged. Nothing through the first four weeks of the season has changed that.

With that in mind, here's a look at the top 10 candidates to challenge Alabama:

Good enough to make Nick Saban lose sleep

No. 2 Clemson (4-0): The Tigers beat Boston College 34-7 on Saturday to start 4-0 for the third straight season, but they actually had their hands full with the Eagles. The score was tied at 7-7 before Clemson exploded for 27 points in the fourth quarter. It was the second time this season the Tigers have struggled at home; they beat then-No. 13 Auburn 14-6 on Sept. 9.

Maybe the closer-than-expected win will serve as an early wake-up call. As Clemson defensive coordinator Brent Venables told reporters Saturday: "What can happen when you win too much is you don't have your guard up."

Clemson is probably the second-best team in the country, but I'm not sure they're as good as they were last season. I still don't think you replace a once-in-a-generation player like Watson overnight. Quarterback Kelly Bryant has been pretty good so far, but the offensive line has to do a better job of protecting him. The line struggled against Auburn and Boston College, which have great pass-rushers, as does Alabama.

But Clemson's defensive line is downright scary -- and better than the Tide's -- and it's capable of putting a lot of pressure on quarterback Jalen Hurts. Plus, Clemson has the confidence from beating the Tide last season.

No. 3 Oklahoma (4-0): During a weekend filled with ho-hum performances by CFP contenders, Oklahoma's 49-41 victory at Baylor might have been the biggest head-scratcher. The Bears had previously been lifeless, losing to FCS foe Liberty, UTSA and Duke to begin Matt Rhule's tenure. But Baylor piled up 523 yards of offense (463 passing) and had a 31-28 lead late in the third quarter.

First-year OU coach Lincoln Riley probably doesn't need to be concerned. The Sooners were laser-focused when they won 31-16 at then-No. 2 Ohio State and vastly underestimated the Bears. But OU's defense will have to continue to improve, and it might have four stiff tests left -- against Texas on Oct. 14, at No. 15 Oklahoma State on Nov. 4, followed by home games against No. 9 TCU on Nov. 11 and No. 23 West Virginia in the regular-season finale.

Don't forget: The Sooners will have a chance to win every time they take the field, as long as quarterback Baker Mayfield stays healthy. Just ask him. Mayfield is the kind of quarterback who has beaten Alabama before (remember Johnny Manziel?), at least stylistically. Mayfield has that irrational confidence that you need to not beat yourself before you get off the bus.

A lot to like, but jury's still out

No. 4 Penn State (4-0): The Nittany Lions have a vastly improved defense and the country's best player in tailback Saquon Barkley. He set a school record with 358 all-purpose yards in a 21-19 win at Iowa on Saturday. He won't be able to beat Alabama by himself. Former LSU star Leonard Fournette couldn't do it, and that's why quarterback Trace McSorley and his receiving corps would have to play big.

Saquon Barkley was sensational against Iowa. Reese Strickland/USA TODAY Sports

What's alarming: Penn State ran 99 offensive plays and piled up 579 yards of offense, but scored only one touchdown until the final play of the game, when McSorley threw the winning 7-yard TD pass to Juwan Johnson with no time left. Penn State proved it can win a tight game in a hostile environment on the road, but it has to do a better job in the red zone.

We'll know a lot more about the Nittany Lions by the end of October; they host No. 8 Michigan on Oct. 21 and play at No. 11 Ohio State the next week.

No. 5 USC (4-0): Is it too early to be concerned about Trojans quarterback Sam Darnold? He has already thrown seven interceptions in four games, after throwing nine in 366 pass attempts last season. But if Darnold were to get hot in the CFP, he's good enough to carry the Trojans on his back, as Watson did for Clemson last season.

The problem is getting that far. USC has won 14 consecutive games dating back to last season, but has struggled to put away Western Michigan, Texas and Cal. Its defense is forcing turnovers -- the Trojans have 10 takeaways in the past two games -- but the offense needs to take better care of the ball.

The Trojans might be on upset alert at No. 16 Washington State on Friday (ESPN & ESPN App, 10:30 p.m. ET) as FPI projects it to be their second-toughest remaining game, with a 56 percent chance of winning.

No. 7 Georgia (4-0): It would be easy to get carried away about Georgia's prospects after its 31-3 demolition of No. 17 Mississippi State on Saturday, especially for a program that has historically struggled to handle success. But this seems to be a different breed of Bulldogs, especially on defense. Second-year coach Kirby Smart, a former Alabama defensive coordinator, is already putting his stamp on the program, and he's following Nick Saban's blueprint.

Georgia's defense is fast and deep, and Davin Bellamy, Lorenzo Carter and Roquan Smith are playing as well as any linebackers in the country. Freshman D'Andre Swift has added yet another dimension to the offensive backfield, and tailbacks Nick Chubb and Sony Michel were already one of the country's best one-two punches.

Georgia's offensive line is still a question mark, and Smart faces a potential dilemma once quarterback Jacob Eason returns from a knee injury. Freshman Jake Fromm has played well enough to keep the job, and Smart might not want to disrupt the chemistry his team currently has. Will Fromm continue to play well in games against No. 21 Florida in Jacksonville, Florida, and at No. 13 Auburn and rival Georgia Tech?

And remember, Alabama hasn't lost to an SEC East team since falling 35-21 at South Carolina on Oct. 9, 2010.

No. 11 Ohio State (3-1): The Buckeyes were left for dead after their 15-point loss to Oklahoma in Week 2, but history suggests Urban Meyer's team will improve dramatically before season's end.

While it's still too early to say Ohio State had fixed its problems on offense, quarterback J.T. Barrett is at least building some confidence against the likes of Army and UNLV. He'll get more chances to pad his stats against Rutgers, Maryland and Nebraska the next three weeks.

If Ohio State is going to climb back into the CFP race, it will have to beat Penn State at home on Oct. 28 and Michigan on the road on Nov. 25. If Meyer can somehow get his team back into the CFP, he and Clemson's Dabo Swinney are about the only FBS coaches who have had success against Saban.

Too soon to tell, but ... maybe?

No. 6 Washington (4-0): The Huskies wanted Bama last year, and it didn't turn out too well for them in the CFP. There's not much reason to think a rematch would be different this season, but the Huskies again look like a Pac-12 title contender.

Ron Chenoy-USA TODAY Sports

While their soft nonconference schedule makes it hard to gauge how good they truly are, the Huskies have plenty of firepower with quarterback Jake Browning and receiver Dante Pettis. Tailback Myles Gaskin finally got going with 202 rushing yards and two touchdowns in a 37-10 win at Colorado on Saturday.

No. 8 Michigan (4-0): The rebuilt Wolverines are showing some early growing pains, especially on offense. They struggled to put away Air Force and then struggled at Purdue on Saturday. Michigan's offense averaged only 3.7 yards per play and had only 131 yards of offense in the first half.

Michigan will have to wait to see whether quarterback Wilton Speight returns this week from a "soft tissue" injury or coach Jim Harbaugh turns over the offense to backup John O'Korn, who went 3-for-3 in the red zone in the second half. Michigan's defense, which lost 10 players from 2016, is already scary good. It held the Boilermakers to 12 yards of offense in the second half.

The Wolverines are probably a year away from being a true CFP contender, but Harbaugh might be good enough to get them there this season. If there are indeed football gods, we'll get to see a Saban-Harbaugh matchup one day.

No. 9 TCU (4-0): For all the talk about Oklahoma and Oklahoma State, TCU coach Gary Patterson is quietly putting together another dramatic turnaround. After a 6-7 finish in 2016, the Horned Frogs put the rest of the Big 12 on notice with Saturday's 44-31 win at Oklahoma State.

The Horned Frogs seem committed to the running game; Darius Anderson had 160 yards with three touchdowns against the Pokes, and Kyle Hicks is expected to return soon. Quarterback Kenny Hill is also playing well, after struggling mightily a year ago. He's completing 72.7 percent of his passes with nine touchdowns and three interceptions.

"Everybody has been waiting for him to fall," Patterson said. "But I've been telling you, Kenny is learning how to win."

The Horned Frogs probably aren't ready to take on Bama, but Patterson made his reputation beating heavy favorites.

No. 10 Wisconsin (3-0): The Badgers have defeated Utah State, Florida Atlantic and BYU, so it's hard to say yet how much of a factor they'll be in the Big Ten title race, let alone whether they'll be in the CFP mix.

Quarterback Alex Hornibrook has been efficient -- he completed 18 of 19 passes for 256 yards with four touchdowns in a 40-6 rout of BYU two weeks ago. The offensive line looks like it's going to be good enough, and there's another deep stable of running backs.

The Badgers should cruise until early November, when they host Iowa on Nov. 11 and Michigan the next week. They don't play Ohio State or Penn State during the regular season. The Badgers probably can't stay on the field with Bama, but we said the same thing about them before they upset LSU in the 2016 opener.

No. 12 Virginia Tech (4-0): For all the talk about the SEC being a one-trick pony, the ACC could really use another team to step up and challenge Clemson. Florida State and Louisville aren't very good right now, and Virginia Tech might be next in line.

The Hokies were supposed to be rebuilding this season, but quarterback Josh Jackson has played exceptionally well, completing 65.2 percent of his passes with 11 touchdowns and only one interception. Bud Foster's defense is as stingy as ever, allowing only 10.3 points per game.

Virginia Tech coach Justin Fuente's stock will be sky-high if the Hokies can upset Clemson at Lane Stadium on Saturday night (ABC & ESPN App, 8 p.m. ET).