ST. PETERSBURG, Fla. — Look: this probably would have happened no matter who the Yankees drew in the playoffs this year (with the exception of their big-spending mirror images up in Boston). The whole notion that the Yankees had shed their image as the Darth Vader of sports for fans outside their fan base was always a temporary thing — if it were ever really a thing at all.

But that’s no longer an issue.

The Oakland Athletics clinched the other American League wild-card berth when the Yankees beat the Rays Monday night, a result that went final in the first inning of Oakland’s game with the Seattle Mariners, one the A’s celebrated with champagne and good cheer following their run-through-the-tape victory over Seattle a few hours later.

And you can make book on this:

An avalanche of baseball fans who at this moment can’t name you five members of the Athletics — (“Hey, they’re the team with the ‘good’ Khris Davis, right?”) — are about to take up the cause of Connie Mack’s old team. For the next week or so, the shortened version of their name has a different meaning.

“A’s” — as in America’s Team.

“We saw in May when we played them the first time that they had a lot of good, young players,” Aaron Boone said Tuesday night, a few hours before his Yankees would put a 9-2 hurting on the Rays and inch ever closer to keeping that game safely tucked within the friendly geometry of Yankee Stadium.

“And now, the last few months, the American League and the rest of baseball can see just how good they are.”

They are also a team that started the season with a payroll of $66 million, the lowest in the sport. They’ve been keeping track of stuff like that since 1988, and the A’s are the first team in those 30 years to reach the playoffs with that designation.

“What we were able to accomplish, with nobody believing in us but ourselves makes it that much sweeter,” A’s third baseman Matt Chapman said in the midst of the frothy party Monday night. “We’re a real team and that’s what real teams do, pick each other up.”

So that’s an easy starting point for figuring out why the country will be lining up against the Yankees next Wednesday, regardless of where the one-and-done play-in is. The Yankees’ Opening Day payroll was $101 million more than the A’s, and that’s grown by a few shekels the past few months.

So that’s one factor, a big one. And let’s be honest: if the A’s do survive the Yankees next week, their fresh wave of followers will stick with them because it’s become just as easy to root against the Red Sox if you don’t happen to root for the Red Sox, the Sox whose Opening Day payroll was $226 million — or just about 3 ½ times the A’s. (The Red Sox will win about 10-12 more games than the A’s across the regular season, so you be the judge if the extra $160 million or so was helpful.)

Fiscal underdogs are always quite popular.

But so are physical underdogs. And that’s really where the A’s improbable imminent popularity comes from. They’ve lost essentially an entire rotation due to various injuries. They have a lot of young players (Chapman, Marcus Semien) and a few guys who were well-known elsewhere (Jed Lowrie, Jonathan Lucroy, old friend Jeurys Familia) and have somehow cobbled together enough wins to elbow their way alongside the Core Fore AL heavyweights in New York, Boston, Houston and Cleveland.

“Nobody expected them to do really anything coming out of spring training,” A’s general manager David Forst told reporters Monday night. “They believed in themselves and they fought through a lot of things, individually and as a group. We lost guys along the way and everyone stepped up. It wouldn’t have happened if they hadn’t.”

The Yankees? Well, a year ago they had a different vibe about them than most Yankees teams do in October because they’d arrived ahead of schedule, stuffed with likeable guys. That aura started to erode the moment they added Giancarlo Stanton, and if we’re being honest there’s a large Yankee-hating element Out There that will treat any team wearing that uniform as the Evil Empire.

But this matchup makes it official.

(And it is official. The Astros clinched the AL West Tuesday after the A’s lost 10-8 to the Mariners in 11 innings.)

It’s a ride that may last only one game and nine innings for the Oakland Upstarts. But America’s Team will be waiting for the Yankees. The Evil Empire has returned in force. And the earth is once again spinning properly on its axis.