The Dolphins hadn’t held a single lead this season.

Until they met the Jets defense.

The previously winless Dolphins entered Sunday averaging just 14.0 points per game — tied with the Titans for fewest in the NFL. But they toyed with the Jets defense — particularly during the first half — during Gang Green’s 28-25 loss at MetLife Stadium on Sunday.

The Jets won the opening toss and deferred, but the Dolphins promptly ripped off a seven-play, 76-yard touchdown drive for their first lead of the season. After the Jets tied it, the Dolphins responded with a 14-play, 60-yard touchdown drive for their second lead of the season — one they never relinquished.

It helped them take a commanding 21-7 lead into halftime. The Dolphins hadn’t even reached 21 points in four of their first five full games.

“Obviously, you don’t want to spot a team 21 points in the first half,” Demario Davis said. “They did a great job of creating some really long drives. They made some good plays. Shoutout to them and the plays that they made. It wasn’t necessarily anything we did wrong on the plays, but they just found a way to make a play in those situations.”

The Jets defense was better in the second half, surrendering just one touchdown. That one touchdown, though, was an unacceptable breakdown that hurt any chance of a comeback.

They trailed 21-17 with under five minutes to go, needing a stop to get the ball back with a chance to take the lead. But Malik Willis completed a pass to a wide-open Caleb Douglas near the left sideline and Minkah Fitzpatrick — who had a chance to stop Douglas for a short gain — took a bad angle and completely whiffed on the tackle.

Douglas went untouched the rest of the way for a 63-yard touchdown that gave the Dolphins a 28-17 lead with 4:44 left.

“We were supposed to have someone in the flat,” Fitzpatrick said. “It was in the flat. But I gotta make a tackle. … We let them make too many explosive plays.”

The Jets defense had one more chance to save face after they cut the deficit to three with 3:24 left in the game. But the Jets gave up two first downs, allowing the Dolphins to run out the clock without the Jets offense getting another shot to either tie or win the game.

They seemed ill-prepared for Willis, who finished with 208 passing yards and two passing touchdowns along with 37 rushing yards and another touchdown on the ground. His scrambling ability helped the Dolphins extend drives, especially in the first half.

“He’s an athletic guy, he’s a talented guy,” Dane Belton said. “No matter what people say about him, as far as the start to this year, he’s had success in this league before. He’s very talented.

“We definitely want to get out to a better start, especially when you put the defense out first. We expect a little different result.”