This was more than Mets magic.

This was more like voodoo. It simply went beyond rational belief. For seven innings, the Mets offense could not even have been called lifeless for fear of insulting cadavers. They had two hits. They were down two runs and were two innings away from being swept at home by the Nationals

“We just went out and took it. That’s all I can say,” Mets manager Mickey Callaway said. “We went out there and the players in that clubhouse took that game.”

OK, so maybe there wasn’t a pact with the devil, but the Mets exploded for nine eighth-inning runs — NINE — for their biggest inning in two years. When all the circling of the bases was done, the Mets sidestepped the sweep and emerged with an 11-5 victory over Washington to halt their mini two-game slide.

“Huge inning,” said an understated Todd Frazier, who had one of the biggest hits in the rally. “Everybody coming up clutch especially with two strikes. … I always say we’re in the game if we’re in grand slam range.”

And they even got a grand slam, by Yoenis Cespedes. But we’re jumping ahead. Want a hero in the inning? Pretty much pick a name.

After three straight singles against Washington reliever Ryan Madson, Frazier singled in two runs to tie the game at 4-4. Juan Lagares, ostensibly the last position player available, pinch hit a two-run double to right to make it 6-4. Later, Michael Conforto, who had one of the original three singles, drew a walk from Sammy Solis to make it 7-4. Reliever A.J. Cole was summoned and Cespedes mashed a Titleist-like shot to left to make it 11-4 with his sixth career grand slam, fifth as a Met.

“It was important to not let the Nationals sweep us,” Cespedes said.

Nine-run innings tend to prevent sweeps. So after Washington starter Tanner Roark snuffed them on two hits over seven innings, the Mets erupted like Vesuvius.

“It’s what we’ve been doing all year. We put at-bats together, we grind out at-bats,” Conforto said. “You’re seeing it’s a little different than last year. It’s not the homer or nothing.”

Down 3-0, the Mets kicked up a fuss, aided by the Nationals defense, in the home fourth. Cabrera led off with a double and Frazier walked one out later. Adrian Gonzalez singled over the leap of Washington second baseman Howie Kendrick, scoring Cabrera, sending Frazier to third. Jose Lobaton then sent a potential double-play bouncer to first. But Zimmerman threw wide of second, everyone was safe, Frazier scoring to make it 3-2. Instead of bunting Matz, Callaway sent up Brandon Nimmo who got plunked by a pitch, loading the bases. Amed Rosario then grounded into a double play.

Washington went up, 4-2, against Paul Sewald in the seventh. Zimmerman tripled and scored on a sac fly.

The win went to AJ Ramos, the second of three strong Mets relievers — Sewald fanned five in three innings. And the eruptions saved Callaway from an ocean of second-guessing. As it was, he settled for a sea of “What was he thinking?”

Callaway made a curious decision when he lifted starter Steven Matz for a pinch hitter in the fourth inning. Matz had a miserable first inning, getting tagged for a three-run homer by Zimmerman, who added a solo shot in the ninth. He threw 33 pitches, many of them stressful with runners on base. But then he settled down and had three perfect innings. Coupled with the last out in the first, Matz retired 10 in a row. Then got yanked for a pinch hitter amid the Mets’ two-run fourth.

When he was called back, he angrily slammed his bat and helmet.

“It was very hard [to yank him],” Callaway said, “but I thought it was necessary at the time, just the way our bats were going.”

The victory eased a lot of tension.

“I definitely understand,” said Matz, who threw 74 pitches and cruised after the first — walked one, struck out six, five of them looking. “I think Mickey would understand I wouldn’t be happy. As a competitor you want to go out there and go as deep in the game as you can and get the ball and go after the guys.”