If you followed Antoine Bethea’s roller-coaster night in Monday’s 37-18 loss to the Cowboys at MetLife Stadium, you saw that it was a microcosm of the entire game for the Giants in that it was a cruel tease.

The Giants veteran safety picked off a Dak Prescott pass on the game’s first play from scrimmage to give the offense the ball at the Dallas 8-yard line. From there, the Giants failed to capitalize completely and had to settle for a field goal.

In the second quarter, Bethea recovered a fumble by Cowboys receiver Amari Cooper after he was separated from the ball by a thundering hit by fellow safety Jabrill Peppers. The Giants offense again stalled in the red zone, settling for another field goal and a 12-3 lead.

On the very next play from scrimmage, Bethea appeared to save a touchdown when he shoestring tackled Cowboys running back Ezekiel Elliott, who burst through a gaping hole in the Giants’ front seven. Bethea ended the run after 15 yards when it looked like it might go for 75 and a touchdown.

Bethea also was involved in the most damaging play of the game — a 45-yard Prescott scoring pass to Cooper that gave Dallas a 30-18 lead with 7:56 remaining in the game, essentially putting the finishing touch on the 2-7 Giants.

Bethea appeared to be the Giants player closest to Cooper as he sprinted on a slant with the ball and dusted the Giants defense en route to the end zone. Giants rookie cornerback DeAndre Baker let Cooper go on his route, with the Giants appearing to be playing zone defense. But when Prescott’s pass hit Cooper between the 1 and the 9 on his jersey, there wasn’t a Giants defender near him.

Bethea appeared to be wrong-footed as Cooper whisked past him.

“That was an assignment that somebody busted,’’ Bethea told The Post, not outing the offending teammate. “I was looking at what I was supposed to be looking at and by the time I saw [Cooper], he was in full stride with a full head of steam and he made a play.”

The killer was the play came on third-and-12.

“That was tough,” Bethea said. “It’s one of those things where we always talk about getting off the field on third down, and it hurt us tonight.”

That was the last part of the roller-coaster ride for Bethea and the Giants, and it was memorable for all the wrong reasons.

“It’s been like that all year,” Bethea said. “We play three good quarters and then there’s one quarter we don’t play well. It’s been a thing for us this year and I don’t know how we can get out of it.”

The shame for Bethea was that he’d gotten his team off to such a great start with that pick to start the game.

“It was a play that [Prescott] hit me with in the first game [the season opener], where I was coming on a blitz and he checked and they ran a slant,” Bethea said. “It was an RPO [run-pass option]. I saw him pull [the ball back] so I figured it was going to be a slant behind me, and I was just trying to get in that window. Once he pulled it, I knew it was going to be a slant behind me.

“It felt good. We got an interception, then we got a forced fumble and recovery. So we got two turnovers. That’s what we always talk about — wanting to start fast and play complementary football. But we just couldn’t finish.”

The story of the Giants — and Bethea’s night.

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