Carlos Mendoza had pitched the manager’s version of a two-hit shutout on Tuesday night, the first game he ever scored in the postseason.

He had deftly relied on his starting pitcher, Luis Severino, and maxed him out. He got two lights-out bullpen efforts from Jose Butto and Ryne Stanek. He smartly gave Jesse Winker the start at DH, then came in for JD Martinez and together they drove in four runs.

He absolutely outshone Brewers manager Pat Murphy and also made his play-off debut as skipper. When Mendoza was playing chess, Murphy was playing Candyland. It was a nice start to Mendoza’s postseason career.

But baseball is funny this way:

If it is a game of capitalizing on traits, as we learn again and again, it is also a game of questionable vulnerability. Today’s genius is tomorrow’s horror. Mendoza probably already knew this. He has been playing for many years. That doesn’t make it any less cruel when you get a bowl full of humble pie for the first time.

“We’ve been knocked down and we’ve shown the ability to get back up all year long,” Mendoza said Wednesday night after his Mets surrendered an eighth-inning lead under a barrage of questionable moves from Mendoza and questionable throws from Phil Maton , dropping a lead. 5-3 game for the Brewers, once again reducing their season to a one-game final.

“We took a hit today,” Mendoza said. “It’s a good baseball club. We are ready to go.”

Had the Mets capitalized on several golden opportunities in the first seven innings, they might have been able to build a bigger cushion than the 3-2 lead they had in the eighth. Had Pete Alonso not tripped over his bat in the first inning, costing the Mets a run they certainly could have used later, things might have felt a little different with a two-run difference.

But managers can’t manage that way. They have to deal with what they have. Sean Manaea had given the Mets five solid innings of work, standing at 86 pitches, and Mendoza knocked over the first domino when he opted not to ask Manaea to do what he’d asked Severino to do 24 hours earlier: eat a sixth inning. So instead of needing nine outs from the bullpen like Tuesday, he needed twelve.

He got half of them easily, with Reed Garrett and Ryne Stanek going six-up, six-down — with the help of Francisco Alvarez shooting a would-be base-stealer. That was because of seven.

And then came the eighth.

Mendoza had three choices. He could go to Edwin Diaz to face the Brewers’ 1-2-3 hitters, but that would be the only inning he could use Diaz, and he would have to pick the ninth with someone else. He could stick with Stanek, but Stanek has only pitched more than one inning twice all year and only once as a Met – all while doing mop-up work in a 7-0 loss.

Also, Stanek had allowed eight home runs in 55 ¹/₃ innings this year as a Mariner and Met, and his fastball, while hitting 98 on Wednesday, is often delectable to fastball hitters — like the Brewers’ young star Jackson Chourio, who had already homered once and was leading in the eighth inning.

“I didn’t like that match with Chourio,” Mendoza later explained. “He’s a really good fastball hitter.”

Behind door number three was Maton, who in 28 ²/₃ innings as a Met had allowed exactly one home run – and none since July 12.

“We wanted the Maton-Chourio match,” Mendoza said, and that’s what he got. And soon, Chourio whistled a two-seater well over the right-field fence to tie the score at 3. Maton then allowed a blistering single to Blake Perkins. He was briefly saved by a double play, then gave up another single, this time to Willy Adames.

Mendoza should have gotten him there. Maton’s round, usually his most lethal throw, was not good: he hung one after the other. Then he hung another one on Garrett Mitchell, and suddenly the Mets find themselves in a familiar position, one game from extinction.

That’s not all about Mendoza, but enough is. Managers make dozens of choices per game. They never ask themselves, “How can I screw this up the most?”

Sometimes it happens that way. Sometimes, even just a day after rolling only sevens, the dice become ice cold. Your stack of chips will be gone in no time. Hard work. Especially in October.