PHILADELPHIA — If losing is a disease, the Mets over the last decade have largely been malaria.

With Wednesday’s 4-0 loss to the Phillies at Citizens Bank Park, the Mets (70-82) were guaranteed an eighth losing season in 10 years, matching the worst such stretch in franchise history.

Noah Syndergaard was flat over four innings, and the Mets lineup was throttled by the Phillies for a second straight night.

The Mets also had eight losing seasons in 10 years from 1974-83, an era that is widely regarded as the dark ages of the organization’s history. Unlike that stretch, the Mets reached the postseason twice — including the World Series in 2015 — during this roller-coaster decade.

Earlier this week, the Mets were eliminated from the NL East and wild-card races. It comes after the Mets started the season with a franchise-best 11-1 record.

“We don’t want to have a losing season, but I don’t want to be one game over .500 and not make the playoffs, either,” manager Mickey Callaway said. “The playoffs and winning the World Series is the ultimate goal and we fell short of that.”

Syndergaard (12-4) allowed three runs on four hits and three walks. Rhys Hoskins hit a solo blast in the first inning before Odubel Herrera’s two-run blast in the fourth completed the scoring against Syndergaard. Lefty Jerry Blevins had a second straight rough appearance, surrendering a run on two hits in the fifth as the Mets lost for the fourth time in five games. They will play their final road series of the season beginning Thursday in Washington.

In his start against the Red Sox on Friday, Syndergaard fired seven shutout innings in which he allowed three hits. Syndergaard’s last loss had come on Aug. 17, also to the Phillies.

“I have been doing things the wrong way for what seems like seven or eight years, I am just trying to reteach my body different mechanics and it’s been a little difficult,” Syndergaard said.

Syndergaard said his mechanical flaw has been a front shoulder flying open, allowing hitters to see the ball, especially his two-seam fastball.

“I am just a work in progress,” he said.

Syndergaard was part of the Mets teams that reached the postseason two straight years. He’s now played for two straight losing Mets teams.

“In 2015 we went on that huge run, it was the best time of my life, and in 2016 I had a little taste of the playoffs,” Syndergaard said. “Over the last two years it has just been real difficult as a player. At the end of the season we will be able to reflect on how this season went and go into next season strong.”