MILWAUKEE — Jose Iglesias and Mark Vientos, half the excellent Mets infield but less than one percent the robust payroll, are the stars hardly anyone saw coming. For a song (and not a song heard as often as Iglesias’ New York hit “OMG”), these guys might rank No. 2 and 3 behind team MVP Francisco Lindor among Mets hitters currently killing it.

Mets baseball president David Stearns seemingly bats close to 1.000 on his moves, but in terms of bang-for-the-buck goodness, the call-up of Vientos and the signing and subsequent promotion of Iglesias continue to top a near-perfect list (see below for a long yet partial list). They are 1 and 1A.

The alleged-underdog, upstart Mets entered their wild-card matchup with the Brewers on a high, won with the playoff-clinching victory down south against the hated Braves, and yet again the out-of-nowhere tandem of Iglesias and Vientos helped keep the flow going here. The Mets’ 8-4 victory in Game 1 was a team effort, but the surprise dynamic duo was again in the middle of things.

Mets owner Steve Cohen knows more about great investments than almost anyone this side of Warren Buffett, and Iglesias and Vientos make a combined $2.24 million ($1.5M for the very veteran Iglesias and the $740K minimum for the kid Vientos), or 0.66 percent of the team’s league-high $341M payroll. The budget is steep but the team easily looks worth it today.

Iglesias’ case is quite the head scratcher. His plight as a .283 career hitter with a great glove who was forced to sign four straight minor-league deals is the one that remains hard to believe. Lindor says he deserves a multiyear contract now, and who can argue that?

Even if he didn’t author the team’s fun theme song as alter ego Candelita, he’s been a joy around the Mets, on the field and in the clubhouse after he was signed originally for Triple-A depth and sure hands.

It’s hard to fathom why he’d become a winter pariah. Teammate J.D. Martinez said, flat out, “Analytics [screwed] him. He hit .300 in Colorado and couldn’t get a job.”

“I don’t think the game has treated me fair,” Iglesias said in response to Martinez’s assertion. “But I’ve got this opportunity. Everything in the past is in the past, and I’m here today [trying] to help this great organization, this great team we have. And I embrace this opportunity with two hands and I’m not going to let it go.”

Iglesias didn’t bat .337 (an MLB best for anyone with 260 at-bats) via luck or his singing talent. He hits the ball consistently hard, and he gathers more infield hits than almost anyone. His teammates will tell you he’s faster than he looks. To which Iglesias says, “I can move.” He also hustles out of the box like almost no one else, and it was that kind of effort that allowed him to beat Brewers starter Freddy Peralta to first with a head-first dive for a game-tying hit in the middle of that game-winning five-run fifth.

Vientos, who leads the club in slugging categories after struggling for a few years to find his footing in the organization, followed two batters later with a two-run hit that gave the Mets the lead for good. Lindor said he’s proud of him. And Vientos said, “I’m super proud. But I’m just so focused on what we have done. I’m not going to stop in the middle and congratulate myself.”

These two guys always believed. It’s only now others are hopping on board.

They aren’t alone among Mets surprises. A list of big contributors who didn’t begin the season with the team is as long as anyone, and counts Martinez, Jose Butto (two perfect innings Tuesday), Ryne Stanek (a perfect ninth), Jesse Winker (a two-run triple), Reed Garrett and Luis Torrens.

It’s no wonder the Mets bandwagon is growing by the day. Chants of “Lets Go Mets,” from behind the visitors dugout could be heard here. The omnipresent “OMG” sign appeared. Times are good around this team from Queens that’s gaining a rep for resiliency and togetherness.

The comebacks this time were less dramatic than down in Atlanta, but they did overcome a couple early deficits. Nothing gets or keeps this team down.

The Mets moved to within a game of a date with the rival Phillies in the Division Series. If they get there they will be underdogs in that one, too.

It’s moves behind the scenes that set themselves up for this great run. Iglesias has to be one of the best minor-league signings ever, maybe behind R.A. Dickey but few others.

Vientos always could rake. But skeptics outnumbered believers for a long time. He was offered in a trade to the Cubs and many others at different times by the previous regime. They weren’t sure he had a position. He’s surprised at third with passable play, and his bat should make a core piece for years to come. He’s already in the center of what’s happening here now. He and Iglesias both are.