Mike Tauchman started it all, drawing the leadoff walk, which sparked a three-run eighth inning. Mike Ford finished it off, blasting the walk-off home run to seal the Yankees’ 5-4 comeback win over the A’s.

The fans who filed into Yankee Stadium on Sunday weren’t supposed to be familiar with either first-year Yankee, who have helped produce a bizarre and memorable season, in which injuries seemingly have no impact on the World Series contender.

The longest-tenured player in pinstripes keeps playing his part, too.

With the Yankees trailing by one entering the ninth, Brett Gardner validated the never-ending optimism in The Bronx, and opened the final frame by crushing a game-tying homer to right off Liam Hendriks. One at-bat later, Ford wrapped up the series with his game-winner.

Prior to Gardner’s shot, Hendriks — who entered with a 1.53 ERA — had converted eight straight save opportunities, and had not allowed a home run on the road this season.

Despite striking out in his first three at-bats, Gardner’s seventh career game-tying or go-ahead home run in the ninth inning or later, wasn’t surprising.

Really, what is after 12 seasons?

“He’s been great. He’s been such a good player between the lines,” manager Aaron Boone said. “For as banged up as we’ve been, he’s been one of the constants. He’s such a grinder. He’s a guy that everyone looks to. The edge that he brings to the ballpark every day rubs off on guys. There’s obviously that leadership element and quality he brings that is so important, but I think it’s really important that we not overlook what a good player he is, and what a good two-way player he’s been.

“I’ve hit him everywhere in the lineup and his ability to get on base, 19 homers now, and still an elite defender in the outfield. … To have the flexibility to move him from center to left, depending on what guys have been down has been huge.”

Despite being by far the Yankees’ oldest position player — no one is within four years of Gardner — the 36-year-old has been among the most durable players on the injury-prone roster, appearing in the third-most games (119) on the team.

With another month left in the season, Gardner needs just two homers to tie his single-season career-high (21). In another two months, the 2009 World Series winner could have some more company.

“We believe in ourselves right now until the very end, even if we’re down a few runs,” Gardner said. “Our fans, I feel like, feel the same way. We can feel that. We feed off that.”

And the Yankees still feed off him.