The postmortem of an NFL season opener usually is bathed in overreaction. Months of buildup for the big reveal often compels fans either to start mapping out the championship parade route or speculating on whom their team will select with the No. 1 overall pick.

Forgive me for being an alarmist after watching Act I of the Vikings season.

What in the name of Les Steckel was that mess?

It’s one thing to lose a first game on the road. But for the Vikings to soil themselves in that manner, on that stage, after having their egos stroked all preseason, good grief, their performance stunk to high heavens.

“What you saw was not a representation of the 2015 Vikings,” said quarterback Teddy Bridgewater, who looked as hopelessly lost as anyone on the field.

He’s probably right, but how do we know what their true identity will be? They’ve played only one game. All we have to go on is what we saw Monday night, and nothing redeeming happened in their 20-3 loss to the San Francisco 49ers.

Nothing.

Of course, the NFL being as unpredictable as it is, the Vikings probably will return home, wallop the Detroit Lions on Sunday and the tone and message will sound different than right now.

This much is certain: The Vikings have much to prove after treating their opener as if it were an exhibition.

“It was just a really, really uncharacteristic performance by our football team,” coach Mike Zimmer said, his exasperation level still climbing.

The offense looked discombobulated. The defense played mindless and uninspired. Their kicker can’t be trusted. And the entire operation felt unprepared.

The amount of mistakes and blown assignments made you wonder what exactly they worked on during training camp.

Zimmer and several players alluded to the possibility that the team got swept up in its own hype, which is absurd if true, because the Vikings haven’t achieved anything of note. They didn’t even defeat a team with a winning record last season.

And yet they were overconfident? Please.

“Everybody has been talking about us for 11 months,” Zimmer said. “Maybe we thought we were a little bit better than we were.”

Being humbled should get their attention. Zimmer covets a tough, physical outfit, so he probably turned three shades of purple watching the 49ers take his team to the woodshed on both sides of the ball.

That was the most alarming development, the mismatch in physical play and lack of pushback.

The offensive line minus John Sullivan and Phil Loadholt predictably took on water, and the front seven of the defense got steamrolled by the 49ers running game. That’s not a winning formula against any team.

What a strange performance, top to bottom.

Adrian Peterson was rendered invisible in his first game back, starting with the first series when he did not touch the ball.

Yes, the 49ers were ready to pounce, but given Peterson’s pent-up energy and threats to run angry after returning from exile, it was mind-boggling that either offensive coordinator Norv Turner or Bridgewater (who can change plays) waited so long to get him involved.

Once he did touch the ball, Peterson looked overanxious and admitted being uncomfortable taking handoffs from Bridgewater in the shotgun. That’s not an issue that gets resolved in one week.

The defining moment of Peterson’s unspectacular return came late in the first half as he watched the final drive from the sideline with his helmet off.

He became a spectator again.

Bridgewater likewise played in a haze. He never appeared comfortable, whether that was because of the pass rush smothering him, or a lack of trust in his leaky line, or a combination of factors.

He just looked out of sorts. He nearly got sacked by his own right tackle while scrambling from trouble, and he threw well short of the end zone on what should’ve been a Hail Mary at the end of the half.

The defense wasn’t any better. That seemed to irk Zimmer more than anything, the fact that his unit played like 11 guys hailing 11 different cabs. Zimmer’s pride and joy looked both clueless and toothless.

“I told the team at halftime, ‘I don’t even know who is out there. I don’t know who this team is,’ ” Zimmer said.

He better hope they were impostors and that this is nothing deeper than one really bad night.

We knew the Vikings had flaws going into the season, but what happened Monday night went beyond minor warts.

That was a gong show.

 

chip.scoggins@startribune.com