FOXBOROUGH, Mass. — One by one, they walked out of the visiting locker room and out of the preseason and began the march toward Dallas at last.

“We’re eager to get this started, man,” Dominique Rodgers-Cromartie told The Post. “We’re going to do something special this year.”

One by one, they guaranteed Odell Beckham Jr. would be making that march on his improving sprained ankle to opening night with them.

“No doubt … none,” DRC said after the Giants’ 40-38 win in their preseason finale. “I just know him as a competitor and as a person. I just see him walking around the locker room, man. He’s good.”

There was Beckham, catching passes from a trainer in the end zone and while on his butt before Davis Webb engineered a drive that allowed Aldrick Rosas to ice the place-kicker job with a 48-yard field goal as time expired to give the Giants a 40-38 victory.

“He’s one of those guys that definitely want to be out there, and he’s gonna be out there,” DRC said.

One by one, a Bring On the Cowboys mentality gripped the Giants.

“Let’s get the ball started and rolling!” Landon Collins told The Post on his way out of Gillette Stadium.

Collins was asked if he has any doubts about Beckham playing against the Cowboys.

“I have no doubts,” he said.

Why?

“I just know HIM,” Collins said.

Free safety Darian Thompson was the only Giant starter who played against the Patriots on a night when both Geno Smith and Josh Johnson acquitted themselves well in their backup quarterback battle and tight end Matt LaCosse caught a pair of TD passes and Kerry Wynn had a pick-six.

“It’s real close … Who wouldn’t want to play in Big D to open up the season?” Jonathan Casillas said.

Beckham did not make himself available afterward.

“I don’t pay too much attention to injuries and stuff like that, but whether it’s really, really, really serious or not healthy or really, really good,” Casillas said, “he’s gonna play regardless. That’s what I think.”

Bill Belichick lost Julian Edelman this preseason. Ben McAdoo has a healthier team than most. There were no catastrophic injuries. A dream preseason in that regard.

“I think we’re all ready to go, man,” Casillas said.

The Giants would not be concerned if Ezekiel Elliott gets to play the opener under the cloud of his six-game suspension.

“Our whole defense is basically back, and Eli’s got some really good weapons on offense,” Casillas said. “Jerry Reese did what he needed to do for us.”

Justin Pugh was asked if he had any doubts about Beckham playing against the Cowboys.

“I don’t think he’s gonna miss Dallas Week 1, ‘Sunday Night Football’,” Pugh said.

Dwayne Harris: “I have no doubt in my mind he’s gonna be there.”

Why?

“Because Odell is a competitor, man,” Harris said. “Anybody who knows Odell, he’s a competitor. He’s gonna do whatever he can to get out there at the first game September 10th. I haven’t really spoken to him or asked him about it, but just looking at him, I know he’s gonna be ready.”

Will Ereck Flowers and the offensive line be ready? Can the Giants run the ball? Will Eli Manning bounce back at age 36 with more weapons than he has ever had in his arsenal? Can the defense be dominant?

“With the talent that we have,” Harris said, “we can be as dangerous as we want to be. We just gotta put the team together and play together as a team and the sky’s the limit for this team.”

Especially with Odell Beckham Jr. reaching to the sky with them.

Bring on the Boys. At last.