ST. LOUIS -- Late last week after a potential go-ahead blast died on the Citi Field warning track, Brandon Nimmo stood in front of his locker and spoke at length about his season-opening slump. Outside of a spate of rotten luck, Nimmo had little explanation. He was hitting the ball harder than he ever had before in his career, while regularly achieving the launch angles necessary for extra-base hits.

Nimmo explained that he was fighting the urge to tinker, fighting the urge to change much in spite of the poor results. Soon he said, he would become “hot as a firecracker.”

He wasn’t wrong.

Nimmo, who hit a tiebreaking home run in the seventh inning Monday to lead the Mets to a 4-3 win over the Cardinals, has suddenly hit safely in nine of his last 11 games. He has two homers and a .317/.417/.561 slash line over that stretch, after batting just .186/.358/.314 over his first 23.

Outside of a few all-but-imperceptible tweaks, Nimmo hasn’t changed a thing. He’s simply running into better luck, and the Mets are benefiting from it.

“I’ve been hitting the ball really well this whole season,” Nimmo said, playfully referencing a recent MLB.com story about his unlucky streak. “I’ve felt like, ‘Hey, it’s coming around.’”

For the Mets on Monday, it continued coming around at exactly the right time. Moments after Sean Manaea served up a three-spot in the bottom of the sixth inning, including a game-tying, two-run double from Iván Herrera, Nimmo stepped to the plate and unloaded on an Andrew Kittredge slider on the inner half of the plate. The 111.1 mph blast matched Nimmo’s hardest-hit ball of the season.

“Pretty majestic,” was how Manaea described it.

That homer made a winner out of Manaea, who allowed only the three runs over six innings. A trio of Mets relievers combined on the rest, including Edwin Díaz, who recovered from his first blown save of the year on Sunday to nail down the final three outs at Busch Stadium.

The effort -- and, more specifically, Nimmo’s blast -- snapped a three-game losing streak for the Mets.

It also helped ease some pent-up discouragement from Nimmo, who was frustrated by his slump despite mountains of evidence that he wasn’t actually doing anything abnormal or incorrect. Nimmo entered Monday’s game ranked in the Top 20 percent of qualified MLB hitters in expected batting average, expected slugging percentage, average exit velocity, barrel percentage, chase percentage and of course -- his signature skill -- walk rate.

For those less analytically inclined, the takeaway was simple: Nimmo was hitting the ball much harder and much more consistently than his traditional statistics indicated.

One metric in particular stood out. The difference between Nimmo’s expected and actual slugging percentages was seventh-largest in the Majors, suggesting he had been one of the league’s unluckiest hitters. (For a multi-day period at the end of April, Nimmo ranked No. 1 on that inauspicious list.)

He did his best not to fret over it. Nor did Mets officials worry, given the quality of Nimmo’s approach.

“We know he’s a great hitter, great player,” manager Carlos Mendoza said. “He’s always going to control the strike zone. And even when he’s not going at his best, he’s going to give you quality at-bats because of the strike-zone discipline, the swing decisions. The on-base is obviously one of his better calling cards, but he can impact the baseball. Now that he’s getting results impacting the ball, going line-to-line, line drives the other way -- that’s who he is.”

Finally, for Nimmo, the process and results are falling into line together.

“I still feel like there’s more in the tank,” he said. “I just try and keep my head down and keep going and just battle every day. Just because you go 0-for-4 or 0-for-5, doesn’t mean that’s the end of it.”