The NFL's new top dog is the ... Kansas City Chiefs?

It's true. Just one week into the season and ESPN's Football Power Index (FPI) believes that, going forward, Andy Reid's team is the strongest in the NFL.

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This isn't a reflection of Kansas City's 1-0 record, or that its one win came against the Patriots. Instead, it's due to of a combination of the prior information the model held about the Chiefs and the degree to which they outperformed expectations in their game against New England.

FPI now believes the Chiefs are 6.8 points better than the NFL average on a neutral field, or about a point better than the Patriots. Kansas City has a 20 percent chance to win the Super Bowl, best in the NFL and ahead of New England at 11 percent.

It took an aggressive move for FPI to get here after just one game. After all, less than a week ago it considered the Patriots 8.8 points better than average and 5.5 points better than the Chiefs.

And then Thursday night happened, when Kansas City hung 42 on New England.

That 42-27 win wasn't driven by pick-sixes or fluky special teams plays that FPI sees as minimally predictive. No, it was a traditional offensive beatdown.

Quarterback Alex Smith chucked a couple deep touchdowns and was ruthlessly efficient with his usual short passes, altogether earning him a Total QBR of 91.8 for the game, second-best of Week 1. Passing plays that involved receiver Tyreek Hill were overwhelmingly positive. And while the ground attack didn't add much from an expected points standpoint, rookie running back Kareem Hunt proved to be an asset in the passing game.

The Chiefs' offense's unit efficiency -- a clutch-weighed version of expected points per play -- was second-best in the league in Week 1, behind only the Vikings. That was pretty meaningful given that heading into the contest FPI considered the Kansas City to have the 10th-best offense compared to the Patriots' second-best defense in the NFL (although it downgraded the Patriots' defense all the way to 16th after Week 1).

What's more, Kansas City accomplished all that on the road.

And so, FPI looked at the Chiefs' performance and upgraded its rating of the Kansas City offense in a major way. Last year's Super Bowl competitors, the Patriots and Falcons, still hold top billing for offensive FPI, at plus-5.3 and plus-5.2, respectively. But the Chiefs now are right behind them, at plus-4.5, a serious threat to any opposing defense.

Kansas City's defense improved slightly from plus-1.2 to plus-1.7 -- and its rank compared to other NFL defenses ticked upward from ninth to sixth -- with the performance against New England. When you're facing an offense quarterbacked by Tom Brady, just keeping them to 27 points is an accomplishment. FPI does not factor in safety Eric Berry's season-ending Achilles injury, but then again, it also does not factor in other non-QB injuries across the league.

And, of course, don't sleep on the Chiefs' top-ranked special teams unit, which we wrote about in the preseason.

All that improvement means that after just one game, Chiefs fans can be just about certain to see their team play January football this year. Well, according to FPI, 90 percent certain.

For more from ESPN Analytics, visit the ESPN Analytics Index.