CINCINNATI — The Mets essentially ran out of pitchers, but they found no such limit of mistakes to make.

With bullpen-underbelly Yohan Ramirez on the mound because manager Carlos Mendoza’s options had severely dwindled, the Mets imploded in one of the uglier eighth innings you will see in a 9-6 loss to the Reds at Great American Ball Park on Saturday, when what was once a three-run lead was wasted.

The Mets (2-6) snapped a brief, two-game winning streak in part because their bullpen arms were depleted, and in part because everything that could go wrong proceeded to go wrong at the wrong time for the Mets.

Ramirez, who had pitched a scoreless seventh, returned for the eighth inning because, “That’s all we had pretty much,” Mendoza said.

Edwin Diaz, Adam Ottavino, Brooks Raley and Drew Smith had been used on back-to-back days. Reed Garrett had thrown 45 pitches Thursday.

Luis Severino went just five innings, which meant Mendoza felt he could only go to Jake Diekman (who pitched the sixth), Ramirez and Pablo Lopez — but there was no bottom of the ninth for Lopez to pitch after an eighth that never seemed to end.

The Mets, who had led 5-2 after five innings and entered the frame up one, watched the Reds break out for five runs on mostly sloppy defensive play.

In the fateful inning, Jeimer Candelario led off with a walk.

Pinch-runner Bubba Thompson appeared to steal second, though a balk was called that gave him the base anyway.

Ramirez struck out Jake Fraley, but strike three skipped past catcher Omar Narvaez, allowing Fraley to take first and Thompson to advance to third.

Ramirez also appeared to beat Elly De La Cruz, whose excuse-me swing sent a soft grounder to the left side.

But Brett Baty gave chase for a few steps before believing Francisco Lindor would grab the ball and then backed off — while Lindor was scrambling toward second base.

A ball that traveled four feet before hitting the dirt and was put in play at just 61.5 mph squirted through the left side for an RBI single to tie the game.

“Weak contact, check swing, probably [have to] keep it on the infield,” Mendoza said.

“It was a check swing,” Ramirez said through interpreter Alan Suriel, “and things just kind of ended up going their way.”

Ramirez did not beat Spencer Steer, who smoked a three-run homer to left that just about ended the game — but did not end the damage.

Two singles and a walk later, the Reds had loaded the bases for Christian Encarnacion-Strand, whose sacrifice fly scored one.

Harrison Bader’s throw home skipped past cutoff-man Pete Alonso, allowing the base runners to move up a base, though Ramirez would strand them on second and third.

By the merciful end, forgotten were the 11 hits and six runs the Mets collected, which qualifies as an explosion for this struggling offense.

Not forgotten were the mistakes that both gave the game to the Reds and, earlier, allowed them back in the game.

In the sixth inning, a Stuart Fairchild single off Diekman scored a run and put runners on the corners.

With two outs, Fairchild attempted to steal second and Narvaez threw down. The throw was too late and allowed Steer to steal home in a play that Little League teams should make.

“Probably should have ate it there,” Mendoza said of Narvaez. “That’s what they do. Double-steal there, and it cost us a run.”

Narvaez, stepping in for the resting Francisco Alvarez, allowed three Reds to steal bases and is 0-for-8 on gunning down runners this season.

With runners on first and third, he realized too late he should not be throwing down to second.

“By the time I thought to stop, I just couldn’t,” Narvaez said.

It was one more mistake on an afternoon filled with them. The Reds’ first run scored in the second inning, when a fly ball from Candelario became a double because left fielder Tyrone Taylor slipped.

Jeff McNeil then booted a ground ball that enabled Candelario to score.

The Mets’ offense has been nearly nonexistent in the first week-plus of the season, which has somewhat camouflaged how poor their overall defense has performed, too.

“We’re a pretty good defensive team,” Mendoza said. “We just got to do a better job of preventing runs in a situation like this.”