Jacob deGrom, meet run support.

It may be a bit of a foreign concept, especially when it comes as early as it did Thursday, but it was a welcome one for deGrom, who took the lead and ran with it.

The Mets pushed across four runs in the bottom of the first and let deGrom take care of the rest on the way to a 4-0 win over the Padres at Citi Field.

“That was good, that was really good,” said Todd Frazier, who went 2-for-3 with a double, two walks and two RBIs. “One of those games where that’s all you needed.”

By taking two of three games from the Padres, the Mets (47-55) have won three of four series since the All-Star break.

Leaning heavily on a slider he threw a career-high 56 times (out of 105 pitches), used to finish off seven of his nine strikeouts and even made an opposing hitter fall over swinging at it, deGrom tossed seven shutout innings. He has not allowed a run in 17 straight innings, working around four hits and a walk against the Padres.

“[The slider is] a devastating weapon when he’s got it going on,” manager Mickey Callaway said. “He broke it out early in the game, which I really liked. He kind of showed that, ‘Hey, I’ve got this, you guys better be aware.’ Then he just started ripping off sliders and they had no chance.”

The only real scare of the day came in the ninth inning, when Edwin Diaz took a 100.4 mph line drive from Manny Machado off his big left toe. Diaz was forced to leave the game to get X-rays, which were negative, leaving Luis Avilan to close out the win.

DeGrom entered the start receiving 3.71 runs per game from his offense this season, which was only slightly improved from the 3.49 it gave him last year. But the Mets got ahead 4-0 in the first inning Thursday — the biggest lead they had ever given him in the first inning during his career. The four runs also marked more support than they had given deGrom in 10 of his 20 starts this year.

“That’s nice. But every time I go out there, I try to think of it as a 0-0 baseball game,” said deGrom, who didn’t have to pretend in his last start, when he threw seven shutout innings against the Giants in a game the Mets lost 1-0 in 10 innings. “The goal is to put up zeroes. And I had great defense behind me today.”

The Padres did not reach second base until the sixth inning. DeGrom still escaped with the shutout intact, though just barely as Juan Lagares nearly misplayed a ball in center field before reaching back to snag it for the third out.

Amed Rosario helped the cause with a pair of fine plays at shortstop, the kind of defense the Mets were missing in Wednesday’s loss.

They were also without timely hitting Wednesday, but capitalized in the first inning Thursday with a sacrifice fly from Wilson Ramos, a two-run double from Frazier and an RBI single from Michael Conforto.

Meanwhile, deGrom was riding his slider. The one he deemed his best of the day made Francisco Mejia fall over while swinging at strike three in the second inning.

“I think I knew [I had it going] before that,” deGrom said. “That’s why I kept throwing it.”

It didn’t show in his bullpen, which deGrom said was “a little wild.” It didn’t matter. The slider he has worked to refine mechanically ruled the day. It looked like his fastball and came out of his hand nearly as hard, but fooled hitters to no end as his ERA dropped to 2.86.

“When it’s like it was today,” Callaway said, “it’s probably the best slider in baseball.”