The Mets have won a series.

This is not a drill. Not a misspeak. Not a typo. The Mets have won a series. Not the World Series, but when you are having a season like the Mets are having, anything that contains “win” or “won” or “avoided annihilation” is viewed as stunningly positive.

“That’s awesome, because it’s been a struggle for us,” center fielder Brandon Nimmo said with classic understatement.

Shut down in order for four innings, the Mets forged a four-run fifth, later added a two-run homer by Jose Bautista and, with Corey Oswalt earning his first major league triumph, went on to a 6-4 victory over the Padres on Wednesday at Citi Field to win their first series in 18 attempts.

“Good homestand. Taking two out of three is nice,” said manager Mickey Callaway. “That’s a stepping stone to where we want to get. We’ve got to go out there and win series. … It hasn’t happened obviously very much lately, or at all lately, until today.”

So beating the Padres two straight after a Monday loss gave the Mets their first series win since May 18-20, when they swept Arizona. With the Mets failing to win any of their subsequent 17 series, select Diamondbacks are alleged to have gone into hiding or witness protection.

The Mets managed this with their big eruption, Bautista’s bomb, more sound defense and a gutty effort by the rookie Oswalt, who pitched his last two innings after jamming his hand while swinging the bat.

“I got jammed (in the third) and then the next two innings I kind of battled through it. I had a tough time getting a grip on the ball because it was kind of swollen,” said Oswalt (1-2) who surrendered two earned runs on three hits, one of them Austin Hedges’ fifth inning solo homer.

But Oswalt, who grew up a Padres fan in San Diego, went five innings for the win.

“Really excited about that. It was a good team win,” said Oswalt who has gone at least five innings and allowed three or fewer hits in three straight starts.

“He jammed his hand in the at-bat. So you saw the four-pitch walk to (Padres starter and loser Clayton Richard). He just couldn’t grip the ball,” said Callaway. “But the way he’s been pitching. He’s earned to see the lineup the third time through.”

A second-inning double-play grounder gave San Diego a 1-0 lead and Hedges made it 2-0 with his shot to left. Nimmo leaped and came away with the ball but replays clearly showed the ball first hit above the orange home-run line. It was ruled a homer after a review.

“All I knew was I had the ball in my glove, so I’m going to play it like I caught it,” Nimmo said.

Callaway lifted Oswalt for pinch-hitter Phil Evans, who stroked an RBI single in the four-run fifth that also contained Kevin Plawecki’s RBI hit and, after a double steal, a two-run, two-out single by Amed Rosario.

Bautista, who made a fine running catch for the third out in the fourth to rob Freddy Galvis with two on, smashed his homer in the sixth to move into a tie for 99th place all-time. Galvis answered with a two-run homer in the seventh off reliever Tim Peterson to make it 6-4. Anthony Swarzak threw the final two innings for his second save.