Clint Frazier of theYankees scores the winning run from third base...

Clint Frazier of theYankees scores the winning run from third base during the ninth inning after a wild pitch thrown by Dellin Betances of the Mets at Yankee Stadium on Saturday. Credit: Jim McIsaac

An erratic, game-losing sequence against his former team made the difference as obvious as ever: This version of Dellin Betances is not nearly the same as the Bronx version of yesteryear.

The Mets lost to the Yankees, 2-1, on Saturday when Betances’ walk-off wild pitch allowed Clint Frazier to scoot home from third. Thirteen appearances and a month-plus into his first season in Queens, Betances has a 6.10 ERA and sharply diminished fastball velocity.

That is not what the Mets (15-17) expected when they made Betances their most expensive offseason addition, signing him to a $10.5 million, one-year contract (including player options for 2021 and 2022).

“I've hurt myself more than anything,” said Betances, who had a 2.22 ERA and was a four-time All-Star in his five best seasons with the Yankees. “Putting guys on, not being able to maybe execute a good pitch ahead in the count. But the free base passes hurt me in the games that I've pitched.

“It's not going to help you as a pitcher, and that's what happened today. I walked the leadoff guy and that's the guy that scored.”

That guy was Frazier, who earlier in the game was thrown out at home trying to score from first on a double.

Betances put Frazier on first on just five pitches. He said he realized quickly that he “didn’t really have much.” But the inning was his. The Mets were going to lose or survive to play extras with Betances on the mound.

“I didn’t think of getting anyone up (in the bullpen) at the moment,” manager Luis Rojas said. “We were sticking with Dellin. When Dellin pitches in big situations, he can get big outs. We were confident he could’ve gotten out of that situation, as well.”

He did not. Betances struck out Brett Gardner, a close friend. But Jordy Mercer looped a single down the rightfield line to move Frazier to third.

Rojas made a mound visit to talk defense with the infield and tell Betances to try to get a ground ball for a double play from Erik Kratz, a 40-year-old backup catcher and career .207 hitter. The Yankees, who snapped a seven-game losing streak, left Gary Sanchez on the bench.

“Obviously he’s a catcher, not great speed,” Betances said of Kratz and Rojas’ game plan. “I was one pitch away from getting out of it.”

Kratz squared up to bunt on an 0-and-1 offering. Betances, trying to throw a high fastball, threw it too high, above the glove of a leaping Wilson Ramos.

Game over.

“It sucks to come in there and not get the job done,” Betances said. “It was just a bad day.”

This season has brought a bunch of bad days for Betances, who has looked off after pitching in only one game in 2019 bdcause of a series of injuries. His fastball has averaged 93.3 mph — a drop of 5 mph from, for example, his 2017 norm.

If that is simply who he is now as a pitcher, is he comfortable with that?

“I gotta find a way on how to make it work,” Betances said Friday. “That’s what I have right now at this moment.”

That rendered the Mets’ comeback — their third in about 22 hours against the Yankees bullpen — irrelevant. Ramos hit a tying eighth-inning homer off Adam Ottavino, who entered when Yankees manager Aaron Boone pulled J.A. Happ after 7 1/3 shutout innings and 90 pitches.

The Mets had three hits and zero walks against Happ.

Robert Gsellman contributed the best of his three starts since joining the rotation, holding the Yankees to one run — on Luke Voit’s first-inning homer — in four frames. He allowed four hits, walked none and struck out four.

The defense helped Gsellman keep it close by throwing out runners at home plate on consecutive plays in the fourth inning.

“Thanks to the boys for having my back,” Gsellman said.

The Mets and Yankees will wrap up this jumbo Subway Series with another doubleheader Sunday. The first three games were decided by a total of four runs.

“It’s nice that the guys are experiencing tight games and clutch situations,” Rojas said. “Start getting used to those because I think we’re going to see plenty in the games that we have left.”