MILWAUKEE — Even Edwin Diaz has limits, and he was not going to be used after throwing 66 pitches the past two days.

The primary setup man, Phil Maton, had pitched three days straight.

Both the closer and the bridge to the closer were closed for the night, which seemed as if it would present a problem for Carlos Mendoza. 

It didn’t.

After the Mets manager rode Luis Severino for six innings, he turned to perhaps the best arm he had left to tear through the Brewers lineup in the seventh and eighth innings. 

Tuesday’s 8-4 Mets win over the Brewers in Game 1 of the NL Wild Card Series at American Family Field will be remembered for the big innings — the three-run second and five-run fifth — but those would have been forgotten if Jose Butto had not breezed through two innings of his own. 

The fringey starter turned shutdown, multi-inning threat saw the best the Brewers had — entering for a face-off with star rookie and No. 2 hitter Jackson Chourio — and sat down six batters straight, three on strikeouts. 

“First time in the postseason, just trying to win this game,” Butto said. “I feel really good.” 

He felt about as good as he had all year.

The righty tossed 1,222 major league pitches this year, and all but three of them were slower than the 96.9-mph four-seam fastball that he unleashed to induce a fly out from Chourio. 

“Chourio’s a really good hitter,” Butto said with a shrug. “I just tried to get him out.” 

He used a hard sinker to strike out William Contreras before getting Garrett Mitchell to ground out. 

Butto returned to the dugout and had a quick chat with Mendoza, who told him to keep going.

So he did. 

Butto’s perfect eighth included a nasty changeup to strike out former Yankee Jake Bauers and a three-pitch punch-out of Rhys Hoskins.

His four-seamer, which averaged 94.2 mph this season, averaged 96.1 mph on this night. Everything was harder, and everything was crisp. 

After six enormous outs on 25 pitches, Butto let Ryne Stanek take care of the bottom of the lineup in the ninth.

A Butto and Stanek night gives Diaz and Maton another day, just like the work Monday from Joey Lucchesi, Adam Ottavino and Huascar Brazoban ensured Butto would have an arm capable of his best heat on Tuesday. 

“He’s been huge. To do what he’s doing right now — that’s how we ended up in this position,” Francisco Lindor said of Butto, who did not complain when he was moved to the bullpen. “Guys got to understand their roles. … That’s the one thing that [David] Stearns and Mendy have asked us from the beginning is to understand your role and give everything you got. Butto has been outstanding this year for us.”