So a glorious run of a New York Mets season, a trip deeper into the terra incognita of the postseason than anyone had reason to expect in midsummer, ended in cascading collapses.

It was as if the Kansas City Royals had made a margin call on much of the joy and luck the Mets experienced this autumn, and not just in that endless and deadening 12th-inning denouement.

A second baseman who stroked home run after home run this October could not pick up a grounder on a critical play; the fearless young closer who had given up not a run all postseason surrendered a crushing homer; the Mets’ alpha dog of a staff ace pitched an artful, dominating final start, only to see one of his fastballs crash against the left-field wall in what was to be his triumphant final inning.

And the first baseman made an errant knuckleball of a throw to the plate, allowing the Royals to tie the score in the ninth inning of a game that the Mets had to win. A night that seemed to offer a stay of execution became only a delayed execution.

For the Mets, the World Series offered an improbable string of sorrows. There was no shame to be found in losing to a superb Kansas City Royals team. The Royals played each game with their chins out, daring the Mets to stop them from taking an extra base, to keep them from fouling off pitches, or from bringing in another deadly relief pitcher.

Sabermetricians like to say there’s no such animal as a clutch hitter. In that case, you hope they slept with eyes shut tight through the Royals’ at-bats. By the third game, with the game on the line, you could more or less type out the phrase “the Royals hit a leadoff single” and have no fear of having to press the delete key.

Royals first baseman Eric Hosmer was as sloppy with his glove as the Mets’ infielders were, but with Matt Harvey looking to complete a season saver of a win Sunday, Hosmer swung tight and hard and stroked a crusher of a double to left.

The greater frustration for the Mets was how often their own miscues and failures laid them low. For long innings in this series, the Mets’ hitters snoozed, and not only against the band of hard-tossing brothers in the bullpen. With two strikes, the Royals shortened their swings and put their bats on fastball after fastball, waiting for one to rap hard.

“Kansas City, they all buy into what their approach is,” Terry Collins, the Mets’ manager, said on the afternoon of this fateful final game. “The deeper you get into the count, the more you cut your swings back.”

The Mets’ hitters, by contrast, swing for the fences and rarely cut down on their swings. (Curtis Granderson offered a series-long exception to that rule, as did Daniel Murphy.) When in rhythm and their timing sweet, Lucas Duda, Michael Conforto and Yoenis Cespedes can offer a wonderful sound and light show, their balls arcing off into the night in the direction of the Willets Point garages.

This series, however, often offered only a disjointed hit here or there. And that meant long soporific stretches in which few Mets reached base.

“The Royals crowd the bases with runners, and that puts on nonstop pressure,” David Wright said the night before.

On Sunday, with the season on the line, the Mets scratched out four hits.

The Mets’ defensive fundamentals bordered on the unsightly this series. Murphy, who carried the Mets through the first two playoff rounds, hitting home runs off the league’s finest arms, stood exposed in the field. He made a terrible and sad error on Saturday, and an only slightly less unsightly one in the inning of the Mets’ undoing on Sunday.

Like anything rare, double plays were cause for celebrations. And Met pitchers are profligate with stolen bases, as if runners are an old-fashioned, 1980s annoyance.

This is not to erase a terrific season from memory. Collins and his coaches coaxed, challenged and spelled when tired the team’s quartet of young starting arms. None of these pitchers throw less than 95 mph, and their command of curves and sliders and changeups speak to good tutors and to a preternatural pitching maturity.

By the end, which is to say this series, the starters looked a bit ragged, as Collins acknowledged Sunday. “I had a pretty good pitching coach tell me the other day on the phone, he said, ‘After I saw them pitch in Chicago, they’re out of gas,’” Collins said.

He shrugged. He’d done all he could to nurse young arms through a far longer season than any of them had previously experienced. “Maybe that’s a fact,” he said.

This said, his ace, Harvey, pitched like the alpha dog that he clearly yearns to be. If he fell an inning short, that might owe as much to Collins’ making too sentimental a play as to any failing by Harvey.

Points of encouragement will be easy enough to find in coming weeks. Shortstop Wilmer Flores’ bat fell silent in the postseason, but his fielding improved and his arm was strong. Granderson resurrected his hitting career this season, and Wright came back from a near-season-long spinal injury, although the precise shape of his future is uncertain. By the last game, he was making soft, boleo-style throws to first base. Taken together with Duda’s terrible throw home, his throw perhaps allowed a not terribly speedy Royal to dart home from third base and slide home with the tying run.

The second-to-last batter in this sad extra-inning battering was the rookie Conforto, a young, powerfully built hitter. He has escape-velocity power to right and grand potential. If you’re sifting the ashes for promising signs, in his last at-bat he eschewed the pull ball and reached out and lined a single to left field. It was nice hitting; like the starting pitchers and Familia, Conforto is young and full of promise.

Away from the multicar pileup that was the final innings of this final game, the Mets can talk of next year as more than just a loser’s cliché. They won a pennant. But there is work to be done.