An 18-point lead had been sliced to two and MetLife Stadium was in a frenzy. Cowboys and Jets fans were on their feet as an all-important two-point conversion approached.

Inside the huddle, all was calm. The Jets defensive players were focused, reminding each other to forget about the penalty-fueled drive that had just produced a Dallas touchdown. All that mattered was the play to come.

“It was really a beautiful sight to see because usually we kind of panic, guys panic, guys are not sure about what’s going on or are we going to stop it,” Jamal Adams recalled. “Everybody believed and we made it happen.”

More specifically, the Pro Bowl safety made it happen. He came rushing up the middle on a well-timed blitz, forcing Cowboys quarterback Dak Prescott to get rid of the ball early as Adams hit him. The pass, intended for tight end Jason Witten — who was blanketed by safety Marcus Maye — was off target, and the Jets had their first victory of the year.

“We’ve been in this situation before, earlier on in the season and we knew how to handle it,” Maye said. “We responded well this time.”

It was a harrowing fourth quarter for the Jets defense, reminiscent of the Week 1 loss to the Bills, when they coughed up a 16-0 lead. This time, they made a play when it counted. There were some nervous moments, as the Cowboys went 75 yards in 10 plays, capped by a Prescott 4-yard rushing TD, to get within 24-22 with 43 seconds remaining. The drive included four penalties on the Jets, three for pass interference. A few could’ve gone either way, including a 13-yard interference call on Adams. But the emotional third-year pro didn’t let it get to him. He regained focus for that final play.

“That’s just like in life, when you get knocked down, you got to keep going,” Adams said. “If it’s the next day or it’s the next play, whatever it is. Just in life in general, you got to keep going.”

The Jets defense has been able to do that, despite the 1-4 start to the season. It has played well, with little help from an offense that had sorely missed quarterback Sam Darnold. On Sunday, with Darnold back after missing three games due to mononucleosis, the Jets took a lead for the first time since Week 1. And the defense led the way to a 21-3 advantage, limiting the Cowboys to just one touchdown in their first six trips into Jets territory.

They nearly gave it all back. But in the end, that defense made one big play to preserve the victory.

“We knew it was going to come down to us,” Maye said, “and we responded.”

It was particularly satisfying for Adams, making the game-winning play against his hometown team. Because of his father George, who played for the Giants, he never liked the Cowboys. And he personally beat them on Sunday.

“How ’bout ’dem Cowboys,” he said when asked about the win’s significance. “I am excited about that.”