For an afternoon, the Mets provided a peek at the kind of ballclub they aspired to be in 2023 long before the losing began.

They were not the team making the mental mistakes. Their bats were the ones punishing pitches over the middle of the plate. They made a physical error, but it did not become a backbreaker because Justin Verlander resembled the pitcher the Mets expected him to be.

The Mets co-ace dominated the Giants through seven innings of a 4-1 victory in front of 34,887 at Citi Field on Saturday.

The Mets (37-46), who only can hope they took a step away from the spiral that has consumed them, will have an opportunity Sunday to win a series for the first time since they completed a sweep of the Phillies on June 1. After a disastrous, 7-19 June, the Mets are undefeated through one July game.

“I constantly see that they respond the next day,” manager Buck Showalter said after the Mets rebounded from a gut-wrenching loss Friday, when they blew a two-run lead in the eighth inning. “There’s a real accountability to try to get where we want to get. The potential’s still there for us.”

Verlander was brilliant, and three third-inning home runs gave the Mets a cushion. But through the last month, Showalter’s crew continually has been burned by mistakes — mental or physical — that have allowed opponents to break through.

The mistake this time appeared in the seventh inning, but Verlander’s brilliance made it forgettable.

With former Met J.D. Davis on first base, nobody out and the Mets leading 4-0, Patrick Bailey grounded to Pete Alonso. The first baseman did not step on the bag, but instead threw immediately to second base — wide of Francisco Lindor and into left field. After Alonso’s second error in as many games, runners were on the corners and the Giants were threatening a second comeback in two days.

But Verlander bore down.

“He doesn’t drop his guard,” Showalter said of the righty, who has a 0.84 ERA in his past five home starts.

Verlander got former Yankee Thairo Estrada to hit into a double play that scored an unearned run. After Blake Sabol (double) and Austin Slater (walk) mounted another potential rally in the inning, Verlander punctuated his day by striking out Brandon Crawford, then pumped his fist twice coming off the mound.

“It’s a big spot. You want to pick your teammate up,” said Verlander, who did not allow Alonso to be the scapegoat for a second straight day.

Verlander, who first was injured and then was inconsistent, may finally be rounding into form. The 40-year-old allowed just one unearned run on five hits with one walk in seven innings. In his past four starts, his ERA has plunged from 4.85 to 3.66.

He has been tweaking his mechanics and found a slider, which he relied on heavily Saturday. He struck out six, lived in the strike zone and induced 11 whiffs on his slider.

“Much better,” Verlander said of his mechanics. “The slider was one of the best things that I can take away from today. … Wasn’t perfect, but was able to make pitches when I needed to.”

He called it “definitely a huge step in the right direction.”

Maybe he is raising the Mets’ low playoff odds, or maybe he simply is raising his trade value. Regardless, Verlander provided rare length for a Mets rotation that has struggled to go deep into games all season.

Drew Smith pitched a scoreless eighth, and Adam Ottavino came in for a drama-free ninth in a rare game that did not provide much anxiety.

It also was a rare game in which the opponent made the mental error. In the fifth inning, Estrada attempted to steal second base on a pitch on which Sabol fouled out. Estrada dove into second, took a step toward third and rounded his way, through the infield grass, back to first base without retouching second, and thus was doubled off.

The Mets only finished with four hits, but three were home runs in the third inning by Francisco Alvarez, Brandon Nimmo and Francisco Lindor.

Their only other hit came an inning later, when a sizzling-hot Tommy Pham sent an RBI double down the third-base line.

That was all they needed because the Mets’ co-ace looked like a $43 million pitcher.

“He was the difference today,” Showalter said of Verlander.