CINCINNATI — In a rotation littered by question marks, Nolan McLean should be the closest thing the Mets have to a slam dunk every fifth or sixth day.

And yet, that version of McLean has largely been lacking, due to high pitch counts causing shortened outings.

Wednesday was more like it for the rookie right-hander, who threw strikes, allowing him to match his longest start of the season in the Mets’ 9-1 victory over the Reds at Great American Ball Park.

Access the Mets beat like never before

Join Post Sports+ for exciting subscriber-only features, including real-time texting with Mike Puma about the inside buzz on the Mets.

The Mets avoided a three-game sweep on a day they totaled 15 hits and jumped to a comfortable lead by the middle innings.

“I think just the fastball command was established in the zone early,” McLean said. “I was able to get some chases late.”

McLean’s performance followed letdowns by Tobias Myers and Kodai Senga that were largely responsible for the Mets losing the first two games in the series.

McLean lasted seven innings (the third time this season he has extended that deep) and allowed one unearned run on three hits and one walk with nine strikeouts. He matched a season high with 101 pitches.

“Sometimes you have better things, and you have different outings,” McLean said, when asked to pinpoint the source of his success. “Today was one of those days when it comes to the fastball.”

In his previous start McLean lasted only four innings against the Braves, allowing two earned runs, and was removed after 93 pitches.

“He dominated that lineup today,” manager Carlos Mendoza said. “It starts with command of all his pitches and he was spot on. He attacked, and the way he was using not only the four-seamer, the sinker, the cutter, allowed him to use the secondary pitches, but man that was pretty impressive there.”

How important is the best version of McLean given the rotation’s troubles?

“Not only from Nolan, but everyone else,” Mendoza said. “I think that is contagious too. Not only what Nolan did today, now we get Sean [Manaea] and then Freddy [Peralta] and then some of the other guys, we need them to step up. They are more than capable, so we trust those guys and they are going to go on a run here.”

Offensively, the Mets received a 3-for-4 performance from Bo Bichette, who reached base four times to continue a torrid stretch. Juan Soto and Francisco Alvarez also provided three hits apiece.

The breakout followed consecutive games in which the Mets were left frustrated with runners in scoring position.

“We finally got the timely hitting,” Mendoza said. “I keep saying it: Those guys are coming to through. Today was a perfect example. It’s a long season and more times than not we will get the big hit.”

The Mets sent eight batters to the plate against lefty Nick Lodolo in the third inning when they scored three runs on four hits and a walk. Soto, Marcus Semien and Mark Vientos delivered RBI singles in succession to give the Mets a 3-0 lead. Luis Torrens’ infield single and a walk to Bichette ignited the rally.

Vientos’ error in the bottom of the inning — he mishandled Zack Short’s throw to first base — led to the Reds scoring an unearned run on JJ Bleday’s sacrifice fly. McLean allowed a double to Matt McLain — on a ball Soto tried to shoestring in left field — before plunking Edwin Arroyo.

Bichette’s single in the fifth started another rally. Soto and Semien followed with singles to load the bases before Vientos’ sacrifice fly extended the lead to 4-1. Alvarez stroked an RBI single and A.J. Ewing’s two-run double put the Mets ahead 7-1. Bichette delivered an RBI single in the eighth.

The Mets return to NL East play on Thursday, when they begin a three-game series in Philadelphia.

“It’s similar to the Braves coming into town,” Bichette said. “[The Phillies] are a great team and we’re going to have to play well to beat them.”