Corey Ballentine attended his first NFL game Thursday night. The free giveaway was a ball from Davis Webb.

The Giants’ rookie cornerback has been a standout early in training camp and continued his strong play by recording his first interception in the preseason opener, a 31-22 win over the Jets at MetLife Stadium.

Ballentine had picked off his teammates three times in practice — twice against Daniel Jones — but finally confiscated a pass from a quarterback wearing a different jersey. It came in the third quarter against Webb as the Division II product raced deep down the sideline step-for-step with Jets receiver Tim White before turning around and leaping to grab the interception.

“[I’m] not letting the playbook get ahead of me and just going out there and playing the game that I’ve played since the fourth grade,” Ballentine said. “It’s just at a higher level now. I just gotta go out there and make plays. This is something I’ve always wanted to do since I was young. Now that the time is here, I just gotta do my thing and make sure everybody knows that I belong here.”

The Giants drafted Ballentine in the sixth round out of Washburn University in April, and his long-shot journey to make the roster was delayed by tragedy. The night of the draft, Ballentine and his college teammate and best friend Dwane Simmons were shot as they were leaving a party in Topeka, Kan. Simmons was killed while Ballentine suffered a gunshot wound to the gluteal muscle and was hospitalized.

The aftermath of the shooting meant Ballentine missed rookie training camp in May, but he has quickly made up for lost time and become a feel-good story along the way.

“I’ve always felt like I could compete at this level with these type of athletes,” Ballentine said. “So the speed of the game wasn’t too different for me. But I think I handled it well. I think I’m fast enough to keep up with them and physical enough to keep up with them as well.”

The Giants have plenty of young defensive backs battling for playing time but Ballentine, one of three drafted this year, has made his impact felt whenever he’s on the field. With another young cornerback, Sam Beal, sidelined in camp by a hamstring injury, Ballentine has taken advantage of the extra reps.

Ballentine nearly added another impact play, when it looked like he had a nice pass breakup covering White on another deep pass by Webb.

But it was negated and turned into a 33-yard penalty when Jets coach Adam Gase challenged for defensive pass interference and won.

“I’m just continuing to improve,” said Ballentine, who added a 40-yard kick return in the second quarter. “Go out here and put my hand in the pile and help this team win a championship, [that’s] my real goal.”