The NFL has been turned on its head earlier than normal.

The Vikings, Chargers, Saints and Seahawks — all of whom missed the playoffs last season — are undefeated after two games.

Welcome back to the NFL, Chargers coach John Harbaugh.

Welcome to the big-boy chair, Seahawks coach Mike MacDonald.

Welcome to a hot-seat reprieve, Saints coach Dennis Allen.

Meanwhile, a slew of supposed Super Bowl contenders are slow out of the gates, whether that’s the 49ers, Lions, Eagles, Bengals or Ravens.

What’s clear, of course, is that the back-to-back Super Bowl champion Chiefs look like the cream of the crop yet again.

For now, anyways.

Here are The Post’s power rankings for Week 3, with several teams making way bigger moves in one direction or the other than you likely will see during any other time this season:

1. Chiefs 2-0 (1)

Given a second life by a fourth-and-16 pass defensive pass interference penalty, the Chiefs capitalized when Harrison Butler hit a walk-off 51-yard field goal to cap a 26-25 victory against the Bengals.

Patrick Mahomes struggled his way to 151 passing yards with two touchdowns and two interceptions.

That’s back-to-back season-opening wins against AFC contenders decided on the final play.

2. Texans 2-0 (6)

Ka’imi Fairbairn kicked four long field goals — including three from 53 yards or further — and the defense had two second-half interceptions in a 19-13 win against the Bears.

Nico Collins went over 100 yards receiving (135) for the second straight game to pick up a rushing attack that was slowed as Joe Mixon dealt with an ankle injury.

3. Bills 2-0 (9)

James Cook ran for two touchdowns and caught another as Josh Allen, who was a four-touchdown superman fighting through injury in Week 1, took a welcome backseat in a 31-10 rout of the Dolphins.

The game’s main storyline was the latest concussion suffered by Dolphins quarterback Tua Tagovailoa.

Allen improved to 12-2 in his career against the Dolphins.

4. 49ers 1-1 (2)                                           

Brock Purdy threw for 319 yards, Jordan Mason ran for 100 yards and Fred Warner created two turnovers, but the 49ers never recovered from the gut punch of Justin Jefferson’s 97-yard touchdown catch in a 23-17 loss to the Vikings.

What’s worse?

Former 49ers backup quarterback Sam Darnold uncorked the long ball.

The 49ers were 3-for-13 on third and fourth downs.

5. Buccaneers 2-0 (14)

In a playoff rematch, Baker Mayfield exacted some revenge on the Lions with a 20-16 win.

He ran for an 11-yard touchdown and connected on a 41-yard touchdown pass to Chris Godwin.

The Buccaneers’ defense notched two interceptions and made two stops in the final minutes, including one at the 6-yard line with 53 seconds remaining.

6. Lions 1-1 (4)

Head coach Dan Campbell had both his offense and special teams on the field at the same, and the “massive error” cost the Lions against the Buccaneers.

Jared Goff threw two interceptions and let go of two other passes that could’ve upped the total to four.

All of it overshadowed an incredible five-sack game (three in the first quarter) from Aidan Hutchinson.

7. Eagles 1-1 (5)

Saquon Barkley giveth, Saquon Barkley taketh away in a 22-21 loss to the Falcons.

A great second-effort play by Barkley created two fourth-quarter points, but a bad drop by Barkley stopped the clock late and then the Eagles defense offered no resistance on the game-winning six-play, 70-yard touchdown drive.

The Tush Push was working well.

Jalen Hurts throwing was not.

8. Packers 1-1 (7)

Josh Jacobs carried 32 times for 151 yards to help backup quarterback Malik Willis win his first in place of the injured Jordan Love.

The Packers ran the ball on 53 of 67 offensive snaps in a 16-10 victory against the Colts.

Willis threw his first career touchdown pass after previously making three unimpressive starts during his Titans career.

9. Jets 1-1 (10)

The NFL’s youngest player, Braelon Allen, scored his first two career touchdowns, including the fourth-quarter tiebreaker, in a 24-17 win against the Titans.

Will McDonald had three sacks — not a moment too soon for a shorthanded defensive line considering that Haason Reddick is holding out and Jermaine Johnson ruptured his Achilles.

Aaron Rodgers got his first win with the Jets.

10. Steelers 2-0 (15)

Russell Wilson’s strained calf kept him from a revenge game against the Broncos.

But Wilson’s Steelers still beat the Broncos, 13-6, with Justin Fields throwing a touchdown pass and the defense posting a shutout through three quarters.

Kicker Chris Boswell is second in the NFL in scoring, accounting for 25 of his team’s 31 points so far.

11. Chargers 2-0 (16)

12. Vikings 2-0 (23)                                              

13. Saints 2-0 (24)

14. Seahawks 2-0 (21)

15. Ravens 0-2 (3)     

16. Falcons 1-1 (19)

17. Cowboys 1-1 (8)

18. Dolphins 1-1 (11)

19. Browns 1-1 (18)

20. Bengals 0-2 (17)

21. Bears 1-1 (13)

22. Cardinals 1-1 (26)

23. Raiders 1-1 (30)

24. Rams 0-2 (12)

25. Patriots 1-1 (22)

26. Jaguars 0-2 (20)

27. Colts 0-2 (25)

28. Commanders 1-1 (29)

29. Broncos 0-2 (27)

30. Titans 0-2 (28)

31. Giants 0-2 (31)

The Giants became the first team in NFL history to score three touchdowns, not allow a touchdown and lose in regulation.

The much-maligned offense did its part — with Daniel Jones throwing two touchdowns and Malik Nabers catching 10 passes, but the defense, special teams and coaching failed in a 21-18 loss to the Commanders, who converted seven field goals.

32. Panthers 0-2 (32)