They got what they deserved. Commit that many mistakes and show an alarming lack of focus, and this is what happens.

The Vikings consumed a large slice of humble pie Sunday.

They didn't just lose. They offered up a historic loss at U.S. Bank Stadium, one of the worst in NFL regular-season history if judged by betting lines and expectations.

Buffalo Bills 27, Vikings 6.

Anyone who predicted that should immediately buy a lottery ticket and buy beachfront in Maui with the winnings.

"Obviously I didn't do a well enough job preparing this football team for this game," coach Mike Zimmer said.

Clearly not. The Vikings looked totally and utterly unprepared to play at a level that suggested they respected their opponent.

The Bills lost to Baltimore by 44 points in the opener and had a player retire at halftime of last week's loss to the Chargers.

The Vikings took them lightly.

Oh, numerous players shot down that theory afterward, saying they gave their opponent full respect. But what were they going to say? Yeah, we thought the Bills would crumple like a wet napkin.

Does anyone honestly believe the Vikings didn't underestimate the Bills and/or get caught looking ahead to their Thursday night matchup against the Rams in Los Angeles?

How else can one reasonably explain such a lethargic, sloppy performance across the board?

Before Sunday, NFL teams listed as 16-point favorites or better had a 75-5 record since 1978. The Bills became the sixth team to pull off the shocker, the first since 1995.

So this wasn't just any random dud. The Vikings joined select company with their no-show.

"Just because somebody says that you're supposed to win doesn't mean that's going to happen," Zimmer said.

Everyone deserves blame. Zimmer. His coaching staff. The players.

Can't blame Daniel Carlson this time.

"As far as being punched in the mouth," running back Latavius Murray, "this is probably up there as the worst there is for me."

Their first half looked like a marriage of Murphy's Law and Charlie Brown trying to kick a football. It was 30 minutes of calamity. The Vikings basically gift-wrapped a 27-0 lead through a comedy of errors.

The defense had two personal fouls on the opening drive and struggled to contain rookie quarterback Josh Allen. Kirk Cousins lost two fumbles on sacks. Special teams had penalties and poor decisions on returns.

The offense managed a measly 46 total yards and two first downs in the half. They didn't cross into Bills territory until 9 minutes, 36 seconds remained in the third quarter. Fittingly, that drive lasted two plays — a drop by Stefon Diggs followed by an interception on a deflection off Murray.

"Nothing went right for us, but that's on us," linebacker Anthony Barr said. "We have to make our own luck."

NFL wisdom cautions not to overreact either way to one game, but, boy, alarm bells were ringing loudly in all three phases.

Cousins' penchant for turnovers came into focus again with three giveaways. Not that his offensive line provided much help with protection.

The Bills sacked Cousins four times and made him look rushed practically every time he dropped back. Defensive end Jerry Hughes ran circles around left tackle Riley Reiff, which is troubling because Reiff is their best lineman. Falling behind by double digits further exposes how problematic the line remains, and there are no quick fixes.

Zimmer's defense continues to look vulnerable, too. Sure, the offense put them in difficult positions with turnovers, but the defense hasn't rekindled the same nastiness that it showed most of last season.

The prevailing thought before the game was that Zimmer's defense would chew up and spit out the rookie Allen. Instead, the opposite happened.

And now another concern has surfaced. Zimmer revealed that defensive end Everson Griffen was not at the stadium because he's dealing with a personal issue.

"I don't have doubts about this football team," Zimmer said.

The performance didn't exactly inspire confidence. And now the Vikings face back-to-back road games, against the Rams and Eagles. Their response to this remarkable flop will reveal a lot about them.

Chip Scoggins • chip.scoggins@startribune.com