Three particular events on the NFL calendar lead to a special amount of overreaction: the first 24 hours of free agency, the first round of the draft and the first week of the regular season. 

Thus, we aren't here to tell you that the Green Bay Packers, Buffalo Bills, Tennessee Titans and New England Patriots are destined to go a combined 0-68. But all four supposed contenders suffered startling upsets along with the Minnesota Vikings, Washington Football Team and very nearly also the Kansas City Chiefs on Sunday. 

It was an important reminder that Vegas sportsbooks clean up for a reason. The NFL is almost comically unpredictable, and we may need to reconsider our expectations for several notable teams and players entering Week 2 and beyond. 

Let's run through some examples from the opening batch of games. 


The Chiefs Might Have a Huge Fight on Their Hands in the AFC

The Kansas City Chiefs ran into limited resistance en route to Super Bowls in 2019 and 2020, but a strong season-opening road challenge by the Cleveland Browns at a raucous Arrowhead Stadium indicates K.C. will have to fight harder than ever to get back to that spot this winter. 

The Browns led the Chiefs for practically the entire game and looked every bit on their level as the Kansas City defense looked vulnerable. The Chiefs offense remains stacked but wasn't able to execute consistently in the red zone, and now it's clear other teams are doing their best to exploit their weak spots. 

Prior to Sunday, the Buffalo Bills and Baltimore Ravens joined Cleveland as the most obvious challengers to Kansas City. But while Buffalo suffered a tough home loss to open its season, the Pittsburgh Steelers reminded us in that game that we can't count them out yet either. Buffalo has too much talent not to rebound, and now the defensively stout Steelers look like a factor again. 

The New England Patriots also looked like they'd again be in the mix this year after Bill Belichick and Co. went on a wild offseason spending spree, and their Week 1 loss to the Miami Dolphins might have had a similar effect as Buffalo-Pittsburgh. The Pats won't fall apart simply because they fell by a single point in their rookie quarterback's debut, and now we definitely have to account for a rebuilt Miami team that could be extremely competitive if second-year first-round pick Tua Tagovailoa can take off at quarterback. At the very least, that Brian Flores-led defense looks as though it could become special. 

Elsewhere, the Cincinnati Bengals and Los Angeles Chargers pulled off mild upsets of their own to start 1-0. Both teams are led by highly promising second-year quarterbacks who are loaded with offensive support, and both defenses have several strong pieces in place. 

If Miami, Cincinnati and Los Angeles can rise up, if Cleveland, Pittsburgh and Baltimore are legit, and if Buffalo, New England, the Tennessee Titans and Indianapolis Colts can bounce back from Sunday losses, the AFC could be a deep gong show in 2021. And that's not ideal for the two-time defending conference champs.


Reports of the Saints' Death Were Greatly Exaggerated

Elsewhere in Upsetland, the New Orleans Saints went out in their first game since Drew Brees' retirement and handed the Green Bay Packers their most lopsided loss under Aaron Rodgers' tutelage.

The 38-3 beatdown was shocking from a number of perspectives, starting with the fact that a defense that sustained several tough offseason losses was utterly dominant against the reigning MVP. Equally as awesome for Saints fans? Brees' replacement, the mistake-prone Jameis Winston, threw five touchdown passes on a turnover-free day. 

The Saints have been crushed by a salary-crap crunch in recent offseasons. Now, Brees is gone. On Sunday, because of the effects of Hurricane Ida on the Gulf Coast, they were forced to play at a neutral site instead of at the cacophonous Superdome. And yet they smashed one of the league's best teams. 

Sean Payton is a special coach, and the Saints remain special. Put the rebuild on hold.