By the end of Sunday, the Yankees turned a potential feel-good game for Anthony Volpe into a brutal loss.

But they need Volpe’s big day to matter more in the long run than the 7-6 walk-off loss to the Mets at Citi Field.

In his fourth game of the season, after undergoing offseason shoulder surgery and then losing his starting shortstop job to José Caballero, Volpe went 2-for-3 with three RBIs, a double and two walks.

It looked like he was going to be the hero after his two-run single in the sixth inning broke a 1-1 tie, but the bullpen surrendered leads of 5-1 and 6-3 to overshadow any positives.

“Incredible: That’s the guy we know,” Aaron Judge said. “That’s why he’s been our shortstop for the last couple seasons, is when we need him in a big spot, he comes up big for us. Made some good plays, had some big swings for us, took his walks when he needed to in some tough situations. He keeps getting more at-bats, more at-bats — he’s coming off a big shoulder surgery, so the first couple games are going to be a little tough.

“But I was definitely encouraged by what I saw today.”

Volpe, who collided with Max Schuemann as both tried to make a play on Carson Benge’s walk-off chopper over the mound in the bottom of the 10th, reached base in nine of his 13 plate appearances in the Subway Series, going 2-for-6 with seven walks — one of which came with the bases loaded Sunday to drive in another run in the seventh inning.

“I’m just trying to stay within myself, stay within my approach and put good swings on good pitches,” Volpe said. “Obviously, it fluctuates, but I just want to stay locked into that. Every day, that’s what I can control.”

Volpe cannot control that Caballero expects to miss only the minimum 10 days on the injured list with a fracture in his right middle finger — he is eligible to return Friday — and that manager Aaron Boone has already said he expects Caballero will get his starting job back when he returns.

But the 25-year-old Volpe at least has the opportunity to give the Yankees something to think about if he can show enough on both sides of the ball while Caballero is out.

Volpe’s first hit of the season came on a 104.5 mph double to the gap off Freddy Peralta in the second inning before he struck out in his second at-bat.

He delivered a two-run single off lefty Sean Manaea with the bases loaded in the sixth to put the Yankees ahead 3-1.

After walking in a run in the seventh, Volpe drew another 3-2 walk against Devin Williams in the top of the 10th, only for Austin Wells to follow by grounding into an inning-ending double play.

“Just trying to do my job and contribute in any way I can,” Volpe said. “I got some good pitches to hit and put some good swings on them.”