CINCINNATI (AP) — When the Mets sent Rafael Montero to the minors at midseason, the message was blunt: Throw strikes or you won’t be back. This time, it sunk in.

Montero gave the best performance of his up-and-down career Wednesday night, taking a one-hitter into the ninth inning. New York held on for a 2-0 victory that extended its dominance over the Cincinnati Reds.

“He’s learning one thing right now: His stuff in the strike zone can get outs,” manager Terry Collins said. “He pitched brilliantly.”

Montero (3-9) allowed only Joey Votto’s double through the first eight innings. Collins decided to let him try for the shutout — he’d never gone more than 7 1/3 innings — and the Reds loaded the bases with one out in the ninth on two hits and an intentional walk to Votto.

A.J. Ramos fanned Adam Duvall and Scooter Gennett for his 26th save in 28 chances.

The 26-year-old Montero realized when he was demoted that it was time to start trusting his pitches and throwing them over the inside part of the plate. It’s been working.

“I think I’ve regained the confidence I had in the minor leagues,” he said through a translator. “That confidence is definitely back.”

It shows in his results. Montero has gone at least five innings and allowed no more than three runs in each of his last four starts, the best such stretch of his career.

Jose Reyes, Wilmer Flores and Kevin Plawecki doubled in the first inning for a 2-0 lead against Homer Bailey (4-7), setting up the Mets’ 12th victory in their last 15 games at Great American Ball Park.

The Mets had won 14 straight against the Reds overall since 2014, a streak snapped by Cincinnati’s 14-4 win…