PHILADELPHIA -- Quietly on Thursday night, the Mets dropped their 82nd game of the season, a 5-4 loss to the Phillies at Citizens Bank Park. With that, they guaranteed themselves a losing season and an unenviable slice of history.

Excluding shortened seasons, the Mets (71-82) are the fourth team in AL/NL history to post a losing record the year after winning 100-plus games, joining the 1986 Cardinals, ‘71 Reds and ‘32 Cardinals.

“It sucks,” said Jeff McNeil. “I think nobody here thought this was where we were going to be at this point in the year.”

The Mets won 101 games last season, which wasn’t enough to win the division; they instead lost to the Braves on tiebreaker rules, then fell to the Padres in a best-of-three Wild Card Series. A record-shattering offseason spending spree did not result in an improved roster, leading to a Trade Deadline sell-off and, ultimately, what happened on Thursday: David Peterson allowed four runs in four innings and Nick Castellanos hit a go-ahead homer off Jeff Brigham in the sixth, sending the Mets to their 82nd loss.

“We all hold ourselves accountable,” first baseman Pete Alonso said earlier this week. “Despite the standings, we all hold ourselves to a high standard of accountability, and also a high standard of performance as well.”

The reasons for New York’s historic tumble backward are multilayered, combining injuries with underperformance, a slow start and other factors -- in many ways, a typical cocktail for disappointment. Opinions on the details vary. An article released Thursday by The Athletic quoted former Mets outfielder Tommy Pham as saying: “Out of all the teams I played on, this is the least-hardest working group of position players I’ve ever played with.”

Manager Buck Showalter declined to discuss that assertion at length when asked about it before the game, responding simply: “Tommy is entitled to his opinion. What works for one player might not work for another. I see the work these guys put in every day. … I don’t need to comment on it. We’ve got other things we need to be on top of -- getting the team ready to play and finish the year.”

There is indeed much for the Mets still to accomplish, including further looks at rookies Brett Baty (1-for-4 on Thursday with an early RBI single but also a key strikeout to strand two runners in the eighth), Mark Vientos (1-for-4 with his third home run in two games) and Ronny Mauricio (just his fourth hitless game since arriving in the Majors). The Mets have spent much of the second half focused on the development of those players, as well as the scaling back of workloads for others.

Through it all, they have tried to compete out of what Showalter has called an obligation of fairness to those with playoff aspirations. That has recently manifested itself in series wins over the Diamondbacks and Marlins, both of whom are in the NL Wild Card hunt. The Phillies, who continue to lead that race, offer a stiffer challenge.

It’s one that the Mets, despite their nosedive to a losing record, still embrace.

“I’ve said this, this entire year: The culture here in this clubhouse, we’re a bunch of high-character individuals that are working toward the same goal, which is going out there and trying to be as excellent as possible,” Alonso said. “The season hasn’t gone as well as we want. But despite the results, we still keep going out there and holding ourselves accountable to a high standard.”