Eli Manning looked so flustered and under fire Sunday night that he had only a slightly worse day than his brother Peyton, who had his sterling reputation put through a blender by the news organization Al Jazeera.

Eli wasn’t forced to defend himself in the court of public opinion over doping allegations.

He merely ran for his life most of the night and appeared claustrophobic against a Mike Zimmer defense that is healthy again and at full capacity.

It was no contest.

The return of a three-headed monster turned the Vikings defense into a menacing outfit capable of doing damage in the upcoming playoffs.

Linval Joseph, Anthony Barr and Harrison Smith returned from injuries, providing an injection of playmakers at all three levels that overwhelmed the New York Giants in a 49-17 thumping that secured a trip to the postseason.

The Vikings defense without its three stars proved to be up to the challenge in recent weeks.

Their defense with those three back in the lineup looks downright nasty.

The defense forced three turnovers, scored on an interception return, recorded six tackles for loss and held the Giants to a 1-for-11 on third down.

“We went out there and dominated,” cornerback Captain Munneryln said.

This Vikings defense — with its full complement of players — is fast and physical and aggressive and well-coached and complex.

And confident. That’s an easy thing to spot.

Zimmer calls defensive plays with supreme confidence, and his players execute his game plan with a similar bravado.

They know they’re good.

Good enough to carry the Vikings deep into the postseason? Possibly.

The offense must pull its weight, and that unit suddenly is peaking, too. A season of tinkering and identity-searching has landed on the right formula with a balanced approach that maximizes both Adrian Peterson’s running and Teddy Bridgewater’s rhythm passing.

But the team’s true identity revolves around defense. Tough, stingy defense.

Their potential was on display at TCF Bank Stadium with a performance that should send them to Green Bay this week feeling confident in their chance to claim the division crown.

“When we’re in the right spots and we tackle well, I feel like we can play with anybody in this league,” defensive end Brian Robison said.

The Vikings circled Manning like sharks in the water and refused to relent.

Manning must have felt helpless without Odell Beckham Jr., his dynamic young receiver who served a one-game suspension for acting like a dunderhead in the previous game.

The Giants were swimming upstream without Beckham to save them.

The Vikings intercepted Manning three times and should have grabbed at least one more. They also sacked Manning four times and made him look more confused than a slacker taking a trigonometry final.

Manning completed only five passes in the first half. He threw a pick-six. He was sacked three times. He posted a Ponder-esque rating of 19.2.

The outcome basically was determined by halftime.

“The guys up front hit him a lot,” Munnerlyn said. “You get around a quarterback’s feet and start hitting him a little bit, you would be worried too. We disrupted him.”

One first-quarter sequence served as a snapshot of Manning’s misery. On second-and-5, Munnerlyn blitzed, causing Manning to throw the ball away.

On third down, Manning appeared confused by a funky blitz design, which resulted in a penalty for delay of game.

On third-and-10, rookie defensive end Danielle Hunter zipped past right tackle Marshall Newhouse for a sack.

On and on it went.

The defining moment for the defense came late in the first half when Smith made a leaping interception and returned it 35 yards for a touchdown, setting a team record with the fourth pick-six of his career.

The whole play was a thing of beauty right up until Smith attempted to fire the football into the stands in celebration. The ball slipped out of his hand and floated harmlessly a few feet, a whiff that undoubtedly will require Smith to accept some friendly ribbing from teammates in the video room.

That was one of the few misfires by the defense on a night when it became healthy and whole again.