MIAMI — Jeff McNeil’s improved production after a disappointing first half has been among the Mets’ best signs offensively over these last six weeks.

Monday night he wasn’t just content to reach base to start a go-ahead rally.

Instead, he became the go-ahead rally.

On a night the Mets struggled with runners in scoring position, McNeil’s ninth-Inning leadoff homer propelled the Mets to a 2-1 victory over the Marlins at loanDepot Park.

The Mets won their second straight and continued their solid play against postseason contenders over the last week: they are 5-3 against a schedule that has also included the Diamondbacks and Reds.

McNeil’s blast — his 10th of the season — came against left-hander Tanner Scott.

Jose Butto gave the Mets a third straight respectable outing since his recall from Triple-A Syracuse by limiting the Marlins to one earned run on four hits with one walk and six strikeouts.

The right-hander has pitched to a 2.08 ERA over those three starts.

The Mets’ rookies in the lineup delivered to produce the game’s first run: Ronny Mauricio singled in the fifth and swiped second (his sixth stolen base since arriving on Sept. 1) and Mark Vientos smashed an RBI single.

The inning also included a walk to Omar Narvaez, but the Mets remained at one run as Luis Guillorme — who was activated from the injured list before the game — hit into an inning-ending double play.

Garrett Hampson’s RBI single in the fifth — the play was originally scored an error — tied it 1-1.

Butto walked Jesus Sanchez leading off the inning before Hampson hit a chopper that took a high hop off Mauricio’s glove and carried into the outfield.

Hampson, running on the play, scored easily.

Jorge Soler’s rocket to left field near the foul pole in the sixth was initially ruled a two-run homer, but umpires convened and changed the call to foul.

The Marlins challenged the call, but the umpires’ ruling was upheld before Soler struck out.

Brandon Nimmo and Franciso Lindor delivered consecutive singles against David Robertson in the eighth, but the former Mets closer struck out DJ Stewart and Pete Alonso in succession to escape the inning.