Brodie Van Wagenen turned heads with his bold offseason trade for Edwin Diaz and Robinson Cano, believing the deal could put the Mets over the top. Turns out, the new general manager’s difference-making move would come one month later.

On a roster in which so many vital pieces still have Sandy Alderson’s fingerprints, low-key acquisition J.D. Davis has been perhaps the most valuable player during the Mets’ remarkable turnaround. In Saturday’s 4-3 win over the Nationals at Citi Field, Davis homered for the second straight game — and fourth time in seven games — and delivered the game-deciding sacrifice fly.

Davis, who sparked Friday’s comeback win with a ninth-inning double, entered Saturday with a .413 batting average in his previous 20 games, and has now reached base safely in each of his past 18 starts at home, while batting .397 with a 1.195 OPS at Citi Field this season.

Davis hit .175 in 42 games with the Astros in 2018. The year prior, he hit .226 in 26 games.

“I think we always believed in J.D.’s bat,” Van Wagenen said before the start of this series. “J.D. has clearly been a breath of fresh air. He’s been a hard worker since spring training. We’ve asked him to play multiple positions, and offensively he’s shown what he’s capable of doing.”

A quiet, sold-out crowd awoke from an hour-long slumber when Davis blasted a two-out, fourth-inning solo shot off of Patrick Corbin, cutting the Nationals lead to 2-1. Watching his 14th home run sail through the sky, the 25-year-old flipped his bat, and jumped in the air.

“That’s just a product of the moment,” Davis said. “I just got hyped. That’s just part of the energy that’s going on. I just run with it.”

While Davis was watching video to prepare for his eighth-inning at-bat, Luis Guillorme tied the game with his first career home run.

“I just ran into the dugout screaming,” Davis said.

Then, he settled down.

With the bases loaded and one out, Davis fell behind on two quick strikes from Daniel Hudson. Davis then fouled off a 97 mph fastball, and followed by taking a slider to right field to put the Mets ahead.

“I’ve been in 0-2 a lot this season,” Davis said. “I never lose confidence in myself. I have a good two-strike approach. I’ve been working to shorten up my swing, and put myself in a situation where I can’t get beat by a fastball.”