49ers tight end Garrett Celek runs past Giants cornerback Janoris...

49ers tight end Garrett Celek runs past Giants cornerback Janoris Jenkins to score a touchdown in Santa Clara, Calif., on Nov. 12, 2017. Credit: AP / Ben Margot

In a lost season filled with so many pathetic moments, Janoris Jenkins may have provided the most glaring evidence of all that’s gone wrong for the Giants.

After being suspended the previous week because he hadn’t shown up after the Giants returned from their bye week, the 29-year-old cornerback put on an absolutely horrific performance in a 31-21 loss to the 49ers on Sunday. Worse than merely missing two tackles and being hopelessly behind Marquise Goodwin on a 83-yard touchdown reception, it looked as if he wasn’t even trying.

If ever there was an example of a player who had quit on the season, Jenkins was it.

Coach Ben McAdoo even took the unusual step of showing the entire team tape of Jenkins’ transgressions, a public shaming that stunned a locker room in need of a swift kick in the behind — even if it was too little, too late in a 1-8 season. Defensive coordinator Steve Spagnuolo was so concerned about the performance that he had a heart-to-heart talk with Jenkins this week.

But Jenkins, one of last season’s most important free-agent additions after inking a five-year, $62.5-million deal, insisted Thursday in his first public remarks since his woeful performance that he was trying his hardest.

“It’s football. I played to the best of my ability. It wasn’t lack of effort,” said Jenkins, who goes by the nickname “Jackrabbit.” “I just think it was lack of technique and staying focused.”

Call it what you will, but there’s no getting around the fact that Jenkins’ awful play was yet another blight on a season gone wrong. With the Giants facing the winless 49ers after a dreadful effort the week before in a 51-17 home loss to the Rams, this was a time when they needed their best players to show up.

Not disappear. Like Jenkins.

At least he ’fessed up to actually making the mistakes, even if he wouldn’t admit he wasn’t trying as hard as he should have.

“It happened, baby. I can’t take it back,” he said. “Nobody’s ever happy when you play that kind of football. But at the end of the day, you have to understand, it’s football. Mistakes are made. They get paid. I get paid. It’s going to happen. So it is what it is. You’re not going to play great every game. Just move forward.”

Spagnuolo covered for Jenkins, refusing to call him out publicly for a lack of effort, but he did acknowledge that he pulled Jenkins aside.

“Janoris and I talked. He obviously agreed he didn’t have his best game and he realizes that,” Spagnuolo said. “We had a good talk, really good. I love that guy. He’s all in, he gives everything he’s got. He missed a few tackles. It was more technique than anything. I’ve got a problem with missing tackles, but I don’t have a problem with his effort. I’m sure he’ll be better this week.”

He can’t be much worse.

The Giants need all the help they can get on Sunday against the Chiefs, who boast one of the NFL’s most vibrant offenses. They come off a bye week knowing that Andy Reid is 16-2 as a coach in games immediately after the bye. And with a well-rested Chiefs offense that features some of the most dynamic players in receiver Tyreek Hill, tight end Travis Kelce and rookie running back Kareem Hunt, the Giants can’t afford another weak effort from their most talented cornerback.

“I think he can play better and he believes he can play better,” Spagnuolo said. “He knows he’s got to play better and we need him to play better.”

There is little to play for other than pride, so Jenkins can at least do himself — and his team — some good by showing up. Which is more than he did last week.

“As a pro, you’ve got to own up to it,” he said of Sunday’s clunker. “You’ve got to man up to it, understand that’s part of football and just move forward.”

First the suspension, then the brutal showing in San Francisco. Time to move on.

“Ain’t no ifs in football, baby,” Jenkins said. “It happened. It’s gone. I’m on to the next game.”

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