PITTSBURGH --The Mets’ offense is clicking on all cylinders, even as the club waits for its top slugger, Pete Alonso, to return to form.

To showcase it, in the first inning of a 13-2 rout of the Pirates at PNC Park on Sunday, J.D. Davis turned on a Polar Bear-like blast to left -- one which manager Mickey Callaway called “an unbelievable poke” -- before the runs came pouring in like the frequent rain in Pittsburgh.

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Davis drove a 1-0 changeup from Pirates starter -- and former Astros teammate -- Joe Musgrove to deep left. He hopped out of the box as the ball caromed off the top of a four-story rotunda. His projected 449-foot drive was the longest of his career and the longest this season by a Mets hitter not named Alonso.

“I knew it was going to go over the fence, but I didn’t know it was going to go to the fourth story,” said Davis, who finished the day 2-for-4 with three RBIs. “I knew I got it, I knew I hit it pretty good, but for how far it went, I had no clue. I just put my head down and started jogging.”

“I haven’t played in this park a ton,” Callaway said, “but even in BP, I haven’t seen anything close to that. And it sounds like they’ve never seen one hit that spot either, from what I hear.”

Davis has arguably been the biggest spark in the Mets’ lineup as they try to prove good on general manager Brodie Van Wagenen’s decision to add at the Trade Deadline. As the Mets have put up a 15-6 record since the All-Star break, including wins in eight of their past nine contests, Davis has compiled a .352/.435/.481 line with four doubles and two homers.

Callaway attributes the success to the preparation Davis makes every game to gain an edge over the opponent.

“[It’s] one thing to have tons of information,” Callaway said. “Sometimes, it can kind of paralyze you, but he implements it the right way in his at-bats. He understands what the pitcher’s strengths are, what they’re trying to do to him and I feel like he probably gets a lot of confidence from that preparation that he does.”

Of course, a 13-run day features more than just one hot hitter.

Todd Frazier, playing first base for the first time since 2017 with Alonso out, broke out of an 0-for-12 skid with a 3-for-5 day, driving in three runs from the No. 3 hole. Robinson Cano was headed for his third double of the day when he roped his 10th hit in five games to right field, but he came up limping between first and second base and exited with a left hamstring strain.

When the day came to a close, six Mets had recorded multihit performances

One of them was starter Noah Syndergaard, who got all the run support he would need in the first inning, and the outburst even led him to move to a heater- and contact-oriented approach. After punching out 11 his last time out, the Mets’ hurler finished with only three against the Pirates, and he saved the bullpen for a doubleheader against the Marlins on Monday.

“When the offense explodes like that and really comes alive, it gives me a nice cushion and changes the way I go out and pitch my game,” he said.

Now, the Mets sit three games back in the Wild Card standings and one win shy of a .500 mark they haven’t reached since May 28 (27-27). They’ll head to Citi Field, where they are 28-28 this season, to try to reach and surpass that mark with a seven-game homestand against the Marlins (four games) and Nationals (three games).

“I think the biggest goal right now is getting back to .500,” Davis said. “I think it would be a huge thing, especially with the hole that we dug ourselves into. And after we accomplish that goal, we can start looking to more of getting into the playoffs and winning series that we’re supposed to win. But right now, we’re just enjoying it.”