ST. PETERSBURG, Fla. — For many of the young Yankees players, spring training only fed the hype machine that had been whirring for months.

Best record in spring training (24-9-1). Decent to sometimes very good pitching. Baseballs consistently leaving the ballpark (49 total, tying the Yankees for third most in the majors).

But all of it, one of those young players said, means nothing come 1:10 p.m. Sunday when the regular season starts against the Rays at Tropicana Field.

“It’s a nice feather in your cap, but this is what counts, right here,” said Aaron Judge, who hit .333 with a .931 OPS in winning the rightfield job. “We could go undefeated in the spring, but it really doesn’t matter for the regular season. So the work starts now. Now it’s time to work, get back to where we belong.”

For the Yankees, that’s the playoffs, where they’ve been once in the last four years (in 2015, when they lost to the Astros in the wild-card game).

They were a drab, going-nowhere .500 team late last July before managing general partner Hal Steinbrenner allowed general manager Brian Cashman to deal off the club’s tradeable assets for prospects and go all-in on a youth movement.

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The Yankees actually played better after the trades of Aroldis Chapman, Andrew Miller and Carlos Beltran. They stayed in the wild-card race until mid-September, finally stumbling at the end to finish 84-78, fourth in the AL East.

Outside expectations are low for this year’s club. Many observers expect growing pains. But a sense of confidence was palpable from the Yankees from Day 1 of spring training, and it only grew as the Grapefruit League victories piled up.

Of course, it is an old baseball truism never to be fooled by what you see in March (September, too), but that doesn’t mean the Yankees look at the gaudy exhibition results as irrelevant.

“Everybody that’s been around the game knows that spring training performance doesn’t . . . you can only take so much out of it,” said reliever Adam Warren who, at 29, qualifies as a veteran in the clubhouse. “But I think what it did for us was build our confidence for this year and kind of show what we can do and the talent level that we have.”

What did Joe Girardi, entering his 10th season as manager and the final year of his contract, feel he learned?

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“Offensively, I think we have a chance to be pretty good,” he said. “You look at our middle of the order, there’s a lot of potential I believe there. And I think you see we have a lot of depth in our organization of young players that are knocking on the door.”

That’s a reference to not-quite-ready prospects such as Gleyber Torres, Tyler Wade and James Kaprielian — to name a few — but the 25-man roster is plenty young.

How young? The Yankees’ likely Opening Day lineup will feature four starters under the age of 25 — Gary Sanchez, Greg Bird, Ronald Torreyes and Judge — which would be only the third time in franchise history that that has occurred, according to the club.

The previous time? Lefty Gomez, Bill Dickey, Frankie Crosetti and Ben Chapman comprised the under-25 quartet — on April 12, 1932.

In fact, the Yankees’ Opening Day lineup hadn’t featured as many as three players under age 25 since April 6, 1971: Bobby Murcer, Thurman Munson and Jim Lyttle.

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“You hope the whole team just picks up where we left off [at the end of spring training],” Girardi said. “We scored runs, we pitched pretty well, we played defensively pretty well.”

Dellin Betances said it’s a group poised to surprise.

“Obviously, right now nobody’s really counting on us. That’s the way I feel,” the setup man said. “But we know the group we have here, the talent we have, and we’re a confident group. I think that goes a long way.”

Added Judge: “I’m just excited to see what we can do. I think that’s kind of what motivates a lot of us, what motivates me: the unknown, how good can this team be? We have a good group of young guys, a good veteran core. We have a chance to surprise a lot of people.”