Mike Ford certainly didn’t seem like he was going to be someone who would be delivering key hits for the Yankees down the stretch, but here we are.

The rookie first baseman became the latest Yankee to blast himself into prominence Sunday, with a pinch-hit, game-winning homer in the bottom of the ninth of their 5-4 victory over Oakland.

It was the second straight day the Yankees toppled the A’s with a walk-off homer, after DJ LeMahieu did it in the 11th Saturday.

Ford’s home run capped a startling comeback that began with a three-run eighth to get the Yankees within a run and continued in the ninth, when Brett Gardner led off against Oakland right-hander Liam Hendriks with his 19th home run.

Ford followed with his 10th of the season in 110 at-bats — and fifth in his last 20 at-bats.

And he finished it with a bat flip as he trotted to first.

“I didn’t even realize I did it until I saw the video,” Ford said.

The 27-year-old didn’t produce much for most of the season, but with the injury-plagued Yankees hit especially hard at first base, he stuck around. And over the last week, he’s had hits in six straight games, going 8-for-20 with the five homers and a pair of doubles.

“A lot of guys are getting opportunities that maybe came earlier than expected and all the guys in the room believe in each other,’’ Gardner said. “No moment’s too big for anybody, as we saw today with Mike.”

Ford joins a group that includes Mike Tauchman, Gio Urshela and Thairo Estrada, to name a few.

“Our guys have been great at it all year,’’ Aaron Boone said of his fill-ins producing in key spots. “Whoever we brought up has controlled situations and moments really well and beyond, maybe, their experience. Ford has been one of those guys, but the list is long.’’

The two late homers changed the tone on a game that saw the Yankees get a much-needed performance from J.A. Happ, who tossed six shutout innings and allowed just one hit. It was the first time the lefty pitched at least six innings and allowed less than three runs since June 6 in Toronto.

But on a day Boone wanted to rest most of his high-end relievers due to their heavy workloads, he went to newly acquired Ryan Dull to start the seventh and the results were predictable. The right-hander, who was claimed off waivers from the Giants after starting the season with the A’s, gave up three quick runs and Chance Adams, recalled from Triple-A Scranton/Wilkes-Barre when rosters expanded Sunday, gave up a homer to Matt Olson to give the A’s a 4-0 lead.

The Yankees were held down by left-hander Sean Manaea, who was making his first start of the season after shoulder surgery nearly a year ago. Manaea retired the first nine batters he faced until LeMahieu’s hard-hit comebacker to lead off the bottom of the fourth deflected off Manaea’s glove for a hit.

The Yankees didn’t break through against Oakland until the eighth.

Tauchman opened with a walk against Jake Diekman, who was then replaced by Lou Trivino. A single by LeMahieu and a walk from Aaron Judge filled the bases for Gleyber Torres, who hit a sacrifice fly to center to make it 4-1 to extend their streak of not being shut out to 220 games.

Hendriks entered to face Gary Sanchez, who fouled out, but Didi Gregorius followed with a two-run single to center to make it 4-3.

Boone went to Adam Ottavino in the ninth for a scoreless inning and then the offense took over against Hendriks.

Gardner snapped a 1-for-17 skid with his 19th homer and Ford — hitting for Clint Frazier — belted his first career walk-off hit and was mobbed at home plate.

“For Gardner to tie it up was huge for us,’’ Boone said. “We got to a couple of really good pitchers at the end that allowed us to steal that one.”