PHILADELPHIA — In different circumstances this would have been the kind of pitching performance that left the Mets convinced the top of their playoff rotation will be just fine.

That might still be the case, just not this year.

Nolan McLean dominated a formidable Phillies lineup Sunday afternoon.

It was just the latest strong performance for the rookie — and maybe his best this season — in leading the Mets to a 6-1 victory at Citizens Bank Park.

The right-hander struck out 10 over six shutout innings, allowing only two hits and two walks.

The Mets won the series rubber game, giving them a shred of momentum to open the post-All-Star break.

But the reality is, the Mets are 16 games below .500.

New York Mets pitcher Nolan McLean (26) throws a pitch during a game against the Philadelphia Phillies. Eric Hartline-Imagn Images

McLean had a sixth straight start of pitching at least six innings, the longest such streak this season by a Mets pitcher.

Along the way his ERA dropped to 3.34 — the lowest it has been since May 19.

McLean, who threw 93 pitches, said reliance on his sinker has fueled his success.

“I try to use it as much as possible because I just want to go deeper into games,” he said. “Getting whiffs is great and all, but it’s really hard to get a ton of whiffs and go deep into games. You have got to have soft contact somewhere in there and I think the sinker is going to be a pitch for me that is going to get a lot of that.”

Other than a choppy stretch that began in mid-May and lasted about a month, McLean has been exactly what the Mets have wanted.

“It’s a lot like a lot of rookie seasons for really good pitchers,” interim manager Andy Green said. “He’s shown flashes of greatness and then he’s had to labor through other parts of the season. But for us I don’t think there’s any way to look at it other than really positive. The stuff is really good.

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“We want him to pitch at the top of the rotation, so the challenge is always going to be out in front of him to continue to move up and get better. But I think when you are talking about rookies sitting in the three-and-change ERA range it’s impressive and we still think you can be more impressive.”

Francisco Lindor’s two-run homer in the first inning got his team started.

The Mets assembled a two-out rally, with Bo Bichette drawing a walk against Alan Rangel before Lindor connected for his sixth homer this season.

Luis Torrens’ RBI double in the second, following Brett Baty’s leadoff single, extended the Mets lead to 3-0.

The Mets loaded the bases later in the inning and received an RBI single from Lindor and Carson Benge’s sacrifice fly for a 5-0 lead.

Juan Soto delivered an RBI single in the sixth that buried the Phillies in a 6-0 hole.

Torrens and A.J. Ewing each singled in the inning.

Alec Bohm homered against A.J. Minter in the seventh to give the Phillies their only run.

Mets shortstop Francisco Lindor (12) celebrates with shortstop Bo Bichette (19) after hitting a two-run home run during the first inning against the Philadelphia Phillies at Citizens Bank Park. IMAGN IMAGES via Reuters Connect

About the only drama McLean faced was in the sixth, when Trea Turner doubled against him for the Phillies’ second hit and Kyle Schwarber walked.

But McLean finished his afternoon strong by catching Bryce Harper looking on a 97 mph sinker.

“[McLean] threw strikes with every single pitch he had,” Lindor said. “He showed how good he is against a really good lineup.”

The double-digit strikeout game was the third of McLean’s career and second this season — his last was on April 21 against Minnesota.

“They have got such good hitters,” McLean said. “You still have got to go right after them and get ahead and baseball is so momentum-related when it comes to count control, so just getting that first strike and trying to beat them to two strikes before you get to two balls is everything.”