On his first touch of the first game of his second season, Saquon Barkley did something against the Cowboys he had never done before and something he has not repeated since during his Giants career.

He fumbled.

The Giants recovered the loose ball — Barkley entered his 22nd career game Monday night (a rematch against the Cowboys) with zero career lost fumbles on 448 combined rushes and receptions — but it set a humanizing tone for the first half of the season.

Barkley missed three games with a high ankle sprain — who knew superheroes were susceptible to ankle pain? — and then cost the Giants a touchdown last week with a brain lapse in the only identifiable weakness in his game.

The pass-blocking Barkley was duped by the Lions on a delayed blitz and didn’t pick up a lateral fumble from quarterback Daniel Jones. He also allowed quarterback hits on back-to-back plays later in the game.

“He gives us a lot in a lot of areas,” running backs coach Craig Johnson said. “Defenses are going to try to attack him — I would — and try to keep him in the pocket. He’ll have to make sure he finds a way to hold up, and we’ll continue to work on that, as with the other things that we have to do, too. I think that’s the biggest and hardest hurdle for most backs coming out of college to the pros.”

Even as he guts through any lingering pain at less than full strength, Barkley is his team’s best player. But for the Giants (2-6) to finish similar to last season — a 4-4 record in the final eight games to create some now-long-gone optimism — he needs to be more than No. 1.

That’s the reality of the way this roster is constructed, with a lack of depth, an offense tasked with making up for the defensive shortcomings and with the possibility receiver Sterling Shepard (third time in the concussion protocol) might be out for the rest of the season.

“Do I think people expect too much out of me?” Barkley said, repeating a question posed to him this past week. “I think the best way to answer that is the same way I answered it when I first got here and people expected it or told me I had to do this or that: I don’t care about other people’s opinions.”

Barkley isn’t going to lead the NFL in yards from scrimmage like he did as a rookie. He isn’t going to finish second for the rushing title, announcing his arrival to the NFL. His three-game absence allowed Dalvin Cook (Vikings), Christian McCaffrey (Panthers) and Leonard Fournette (Jaguars) to turn those numbers into a three-horse race.

“I think it’s important to get him going,” coach Pat Shurmur said.

The Giants play five games against the NFL’s top-10 rushing defenses during the second half of the season, beginning with the Cowboys. Road games against the Jets and Bears are up next as well as two games against the Eagles.

Barkley averaged 68 rushing yards over his first two games back from injury, but he actually endured three instances of back-to-back games with a lower average as a rookie. Two of those three times he responded with 100-plus yards in the next game, so Barkley might be sitting on another monster performance.

“I think the [offensive] line is doing a good job of getting movement, creating movement up-front, stopping penetration,” Barkley said. “Playing from behind doesn’t help the running game. You have to take notice of that. You have to take it play by play. When the opportunities come, make them pay for it.”

One way Barkley still is playing like a superman is his ball security. Hall of Famer LaDainian Tomlinson once went a record 1,001 carries without a fumble and Barkley might challenge the mark one day.

“He brought that here from Penn State,” Johnson said. “When he’s been here he’s done a really good job of taking care of the ball, but I don’t lose [sight of] that just because he has [secured the ball]. We still practice that all the time.”

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