NEW YORK — One National League postseason contender reignited its playoff push this week while another continued its downward spiral as the Chicago Cubs pulled off a stunning sweep of the New York Mets, winning the finale of the three-game series at Citi Field 4-1 on Wednesday.

“Especially with them in the wild-card hunt, and right behind us, to take three from them and kind of distance ourselves from them puts us in a great position,” Cubs third baseman Kris Bryant said after the game.

For Mets fans, it might not have been all that stunning to get swept at home, considering it just happened to the team over the weekend when the Atlanta Braves slowed New York’s second-half surge. But when you combine the Mets’ overall home record (now 37-27) with the Cubs’ road woes (28-39) — and who the Mets were pitching the past three nights — you start to see why the visitors were so excited.

“The biggest thing is coming into New York and [beating Marcus] Stroman, [Noah] Syndergaard and [Jacob] deGrom,” Wednesday’s winning pitcher Jon Lester said. “That’s the big thing for us. It’s a big confidence booster for our hitters.”

No one got a bigger boost than Cubs backup catcher and first baseman Victor Caratini. Filling in for an ailing Anthony Rizzo at first, Caratini homered twice on high sliders from deGrom, driving in all four Chicago runs while leading his team to its first road sweep of three games or more this season — of a team not named the Marlins.

“That’s the kind of things we’re going to have to do to retake first place in the division and keep going forward,” Caratini said through the team interpreter.

He’s not wrong, as all season the Cubs have bounced between extending a lead at the top of the NL Central and threatening to miss the postseason altogether. At home, they dominate; on the road, they struggle. But over the past week, they’ve turned things upside down. After sweeping the Giants at home, the Cubs were swept at Wrigley Field by the Nationals. That came right before this road sweep of the Mets. Go figure.

“It’s kind of been a weird last nine days,” Lester said.

As for the Mets, their playoff hopes are on life support as they fell five games behind the Cubs for the second wild-card spot. Either reality hasn’t set in or the Mets are simply clinging to their slim mathematical chances, even with a month to play. It doesn’t look good, but don’t tell that to Mets manager Mickey Callaway.

“These guys can do something special,” Callaway said. “I know they believe that. … We’re going to continue to push and push and push until the end and see where we come out.”

It’s not likely to be on top, not with three other teams battling them to overtake the Cubs and/or Nationals, current holders of the two wild-card spots. Of course, the Cubs want no part of the wild card. They’ve been there two of the past four years and neither season ended with a World Series appearance. They’d prefer winning the NL Central and skipping the play-in game.

It’s why the Cubs have to continue to change the narrative on the road. They’ve won their past two series away from Chicago, after going three calendar months without winning one. It has been so frustrating that manager Joe Maddon has broken it down to issues specifically on the road and at night, as the Cubs were 16-32 in road night games before the past three nights.

“If you put it into four quadrants, day/night at home, day/night on the road, we were screwing up with one quadrant,” he said. “I have no idea why. These three [games] check the worst quadrant we had.”

A five-game road win streak — including four in a row at night — might make believers out of those who gave up on the Cubs long ago. Three months without a road series win will turn off many a fan — just as being swept at home in consecutive series will. The Cubs might not win their division, but Mets fans have plenty more about which to be upset.

“You come in, know that you’re playing them head-to-head and you want to go win the series so you can create your own destiny,” Callaway said of facing the Cubs.

It didn’t happen for New York and now we’re left to see whether each team’s storylines this week continue or get turned upside down again. Both teams have been hard to figure out this year.

“Going into the series I thought two out of three would be great,” Bryant said. “To take all three, it feels great. It makes our road record look better.”

Lester added: “This whole series was huge for us. We all know our road woes.”

Which makes the hurt that much more intense for the Mets. Their big chance against a team they needed to beat fell apart. After giving up two home runs to one of the unlikeliest power sources on the Cubs, deGrom summed things up succinctly.

“That one stings,” he said.

The Cubs can relate. Just not this week.