Edwin Diaz’s air of invincibility turned smoggy Monday night in the first real letdown of the stud closer’s Mets career.

“I have pitched well, but I was ready I guess to take the loss because I don’t think I am going to have many more this season,” Diaz said after allowing a solo homer to the Reds’ Jesse Winker in the ninth that sent the Mets to their fourth loss in five games, 5-4 at Citi Field.

Diaz, who had been unscored upon in 10 of his 12 appearances this season, got two quick outs in the ninth before Winker turned around a 96-mph fastball and cleared the right-field fence.

The Mets (14-14) had overcome a shaky second inning from Zack Wheeler to tie the game, but never got the hit they needed to overtake the Reds, who received 5 ¹/₃ scoreless frames from five relievers.

According to FanGraphs, Diaz entering play had missed bats with 46.7 percent of his pitches this season, the highest miss-rate among qualified relievers. Left-handed hitters were also 0-for-14 against him with 10 strikeouts, but the lefty-swinging Winker didn’t miss.

“I was trying to throw it inside, just catch him, but I left it over the plate and he hit it pretty hard,” Diaz said.

Wheeler was sharp in every inning except the second, and it cost him: the Reds sent nine batters to the plate in that inning and scored four runs. Overall, the right-hander lasted six innings and surrendered four earned runs on seven hits and three walks with four strikeouts, departing after 94 pitches.

Callaway visited the mound with the trainer in the fifth, concerned that Wheeler’s velocity had dipped to 91 mph on a fastball. But the right-hander convinced Callaway he was fine to continue.

“When we took him out [after the sixth] he said he wanted to go back out,” Callaway said. “So he kind of squashed that concern.”
The outing broke a streak of three straight quality starts for Wheeler, a stretch in which he was 2-1 with a 2.25 ERA after two sluggish performances to begin the season.

“It’s a frustrating one, just because of that [second] inning,” Wheeler said. “Other than that I think it went well, but the second inning I was a little up out of the stretch and walked some people.”

Jeurys Familia nearly put the Mets behind in the eighth — walking Scott Schebler and drilling Jose Iglesias to begin the inning — but Todd Frazier turned Jose Peraza’s hard grounder into an inning-ending double play.

Juan Lagares’ catch, just before hitting the center-field fence, on Joey Votto’s smash in the seventh kept it 4-4 in an inning Seth Lugo surrendered a leadoff single to Peraza. Lugo escaped the inning, with the go-ahead run at second base, by striking out Yasiel Puig after getting a replay reversal that showed Puig wasn’t hit by a pitch.

Tanner Roark and his replacement, Wandy Peralta, struggled to throw strikes in the fourth, allowing the Mets to tie it 4-4. After Roark walked Pete Alonso on four pitches with the bases loaded for the inning’s first run, Peralta issued a four-pitch walk to Brandon Nimmo.

Lagares drew a two-out walk to begin the rally before Wheeler slapped a single — raising his batting average to .303. Jeff McNeil walked to load the bases.

The Mets had pulled within 4-2 in the second on Amed Roasrio’s RBI single after Michael Conforto and Wilson Ramos had doubled in the inning, with Ramos’ hit producing a run. The extra-base hit was Ramos’ first since April 16, when he homered at Philadelphia.

Wheeler watched the Reds grab a 4-0 lead in the second. Jose Iglesias delivered an RBI double and Tucker Barnhart singled in a run before Wheeler recorded the inning’s first out. Peraza stroked an RBI double in a rally that began when Wheeler walked Puig and Schebler in succession to begin the inning.

“The starter’s job ultimately is to keep us in the game and give us a chance to win,” manager Mickey Callaway said. “I think that was a successful outing because [Wheeler] kept us in the game.”