NEW YORK -- The future was laid out before the Mets, plain to see: one at the plate, one in the on-deck circle, one near the dugout exit awaiting his turn to bat. The Mets were trailing the best team in baseball by three runs in the ninth, but they at least had some hope. They at least had the kids.

First it was Brett Baty, long one of the organization’s top prospects and a spark for the club throughout the early season. He struck out. Next up was Mark Vientos, the story of the day, a prospect who woke up in Syracuse, N.Y., but arrived in Queens in time to hit a game-tying, two-run homer in the seventh. He flew out.

That brought up Francisco Álvarez, the organization’s top prospect entering the season who had mostly struggled at the plate since his callup. Just not on this occasion. Álvarez launched a game-tying, three-run homer off Jason Adam, allowing the Mets to steal a walk-off, 8-7 win over the Rays in the 10th inning on Pete Alonso’s three-run homer.

“Three homers to end it is something from a movie,” starting pitcher Kodai Senga said through interpreter Hiro Fujiwara.

Were a scriptwriter to pen this sort of ending, they might have dismissed the first of those homers as a bit too cliché. On his first night back in the Majors after all but forcing the organization into a callup, Vientos crushed a game-tying shot to straightaway center field in the seventh. But the excitement from that homer was short-lived, as the Rays -- known for their relentless brand of power -- built another three-run lead that they carried into the ninth.

By that time, what was left from a paid crowd of 29,695 at Citi Field had returned to its habitual booing -- at least until Adam gave the first two batters of the inning free admission to first base. Due up next were the kids: Baty, Vientos and Álvarez in order.

At Syracuse, those three tended to bat all in a row, leading them to declare frequently that if one couldn’t get the job done, the next in line would. So when Baty and Vientos both recorded outs to bring the Mets within a whisper of another loss, Álvarez steeled himself at the plate. He thought about his own first week back in the Majors about a month ago, when Padres closer Josh Hader threw fastball after fastball above the strike zone, goading him into a disheartening strikeout. Álvarez vowed to make this outcome different.

Fortunately for him, Adam provided the opportunity that Hader never had, throwing a looping sweeper over the heart of the zone. Upon drilling it 426 feet off the facing of the second deck in left, Álvarez took a few steps toward first base, screamed, then thundered his bat into the air.

“I said if [Baty and Vientos] can’t do it, I want the opportunity to be able to do it,” he said through interpreter Alan Suriel. “And I was able to do it.”

Finally, after the Rays scored twice in the 10th to put New York once again on the brink, it was Alonso’s turn. The first baseman’s walk-off credentials were already well-regarded by the time he stepped to the plate in the 10th, but this time he was facing an additional challenge: a sinus infection so severe that Alonso had slept in a separate bedroom from his wife to lessen her risk of catching it. Still, Alonso’s mantra is that “if I’m physically able to, I’m going to go out there,” so he told Buck Showalter to forget any idea the manager might have of benching him.

When Alonso sent his fourth career walk-off homer into the night, he matched five others for the most in Mets history. Three of his four walk-offs have come in extra innings, which also tied a franchise record.

“Just a very unfortunate time to be the lesser Pete,” said Pete Fairbanks, the Rays' reliever that served it up.

As Alonso rounded the bases, his teammates spilled out of the dugout in what looked and felt a bit like a catharsis. All season, the Mets have waited for a moment like this, after experiencing so many of them last summer. All season, they searched for a spark.

Finally, on Wednesday, the youngest among them provided it.

“It’s always exciting when you see a young guy come up wanting to succeed and make an impact,” Alonso said. “Obviously, they made a huge impact for us tonight.”