Sandy Alderson couldn't believe it, couldn't believe how the game could be so cruel. The rawness of the last 24 hours hadn't subsided. Yet here he stood, in the depths of Citi Field, on a miserable rainy afternoon in late July, seething at what flashed across the television screen.

Justin Upton had just hit a go-ahead homer in the ninth inning for the Padres, sending the Mets careening toward a wrenching 8-7 defeat. It had come on the heels of a debacle.

The night before, Alderson thought he had landed the final piece in a daring in-season reboot, trading for Brewers centerfielder Carlos Gomez. The deal fell through over concerns about his hip. But first, rumors of the pact reached the playing field, right in the middle of a game. Shortstop Wilmer Flores, thinking he had been traded, was reduced to tears.

Now, a day later, Upton entered his home run trot just before a downpour forced umpires to stop play. More than an hour passed before the Mets quietly made their final three outs.

With his team inching closer to wasting a season that began with so much promise, Alderson stewed in his misery as he awaited the inevitable. But as the rain fell, his frustration gave way to something else.

"In the hour and a half that ensued, it was like 'OK,' " said Alderson, who could not know the extent of the transformation that was just ahead. "I had sort of come to grips with it and I was ready to go."

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Luck resides at the center of it all, always. Winners or losers, dynasties or cellar-dwellers, they are all resigned in some way to fate. There is no way to know when it will present itself or when it suddenly will depart. But without fail, it will happen.

For the Mets, fate intervened during one of the most defining six-week stretches in the franchise's 54 seasons.

It began with the July 31 non-waiver trade deadline, the last-minute acquisition of Cuban sensation Yoenis Cespedes and the start of a three-game sweep of the Nationals, the franchise with which the Mets would be inextricably linked. It ended on Sept. 9 with another sweep of the Nationals in Washington.

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In between, the Mets forged the identity that they brought with them Friday night against the Dodgers in Game 1 of their National League Division Series. They emerged as a complete team, stronger, healthier, deeper than they had been before. Suddenly, they truly believed they could not lose.

"What we did during that period of time set the tone," manager Terry Collins said.

Tim Teufel, the Mets' current link to the 1986 championship team, rose to speak. He remembered the way New York buzzed when the Mets ruled the baseball world. He wanted that feeling again. On July 31, that vision became a reality.

Collins had never seen Citi Field come alive as it did when the Nationals came to town with a three-game lead.

"We knew this series against them in our park was a defining moment," Collins said.

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Flores, his tearful outburst still fresh, set the tone with the biggest swing of his life -- a walk-off home run.

"It kind of unfolded slowly," Alderson said. "It was a low-scoring game. But when Flores hit the home run, it was kickoff."

The Mets completed the sweep to pull even in the NL East.

"I think what that did was take our confidence to another level, which helped us then go into Washington and sweep them,'' Alderson said.

By the time the Mets arrived at Nationals Park Sept. 7 for the start of a three-game series against the Nationals, they had taken a four-game lead. Cespedes entered a historic tear. The rest of the lineup followed suit. The time had arrived to seize control of their own fate.

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The Mets defied every expectation. Three times they fell behind the Nationals. Three times they rallied to win in improbable fashion. The lead had grown to seven games.

"I don't think any of us really expected that we'd be seven up,'' Alderson said.

"That's when I knew that this could be destiny," said J.P. Ricciardi, Alderson's assistant.

The first sweep of Washington began a 31-11 stretch that left the Nationals in the dust. By Sept. 14, the Mets led Washington by 91/2 games.

After four years of painful rebuilding, the Mets clinched on Sept. 25 in Cincinnati.

Through an ability to react swiftly at the trade deadline, the Mets had transformed their identity. But as the days leading up to that critical six weeks had proved, there was another reason.

"There's always some luck involved," Alderson said. "Any success you have, there's a fair amount of luck involved. We readily admit that."