WASHINGTON -- Before Tuesday’s series opener against the Nationals, manager Mickey Callaway, in defending catcher Wilson Ramos, mentioned that the sub-.500 Mets were six games above that mark on nights Ramos started. No matter that both traditional and advanced metrics painted a less appealing picture of Ramos. The Mets, Callaway said, considered their win-loss record with Ramos more than mere coincidence.

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Three hours later, as if to prove it, Ramos snapped out of a slump to deliver easily his most impactful hit as a Met: a first-inning grand slam in New York’s 6-2 win at Nationals Park. Ramos also caught all eight of Noah Syndergaard’s innings in a winning effort, offering the Mets assurances that they won’t regret the two-year, $19 million deal they gave him this winter.

“If he hits grand slams, he’s going to continue [winning],” Callaway said.

For Ramos, it was a slam that nearly didn’t occur. Facing Nationals starter Jeremy Hellickson, Robinson Canó hit into what appeared to be an inning-ending double play. But the Mets successfully challenged that Gerardo Parra dropped the ball at first base, allowing the Mets to extend the rally -- which they did, with a hit and a walk. That brought up Ramos, who bashed his grand slam over the left-field fence, prompting his teammates to mime buffalo horns on their heads -- a reference to the sturdy Ramos’ nickname, “Buffalo.”

“It’s good when you start the day hitting the ball well,” Ramos said. “You get more confidence in the next at-bat. The next at-bat, I felt more relaxed at the plate because in my mind, I know that I already homered. I’d say I made my night with that.”

The Mets didn’t do much else against Hellickson, nor did they need to. Syndergaard kept the Nationals hitless until the sixth inning, when Wilmer Difo singled and Victor Robles hit a two-run home run. Syndergaard lasted eight innings, striking out six and allowing four hits, and Dominic Smith tacked on a late insurance run with a solo homer.

“To jump on the Nationals was great,” Smith said. “It was huge for us.”

It was huge in particular for Ramos, who entered the night batting .161 with just two extra-base hits in his previous 19 games. Callaway mentioned that the Mets, entering a stretch of 20 games in 20 days, will need to lean more on backup Tomas Nido in the coming days. But he also went out of his way to say that was no slight on Ramos, the clear starter, whom the Mets see as a presumptive offensive force at catcher.

Although the Mets never expected Ramos to be a standout defender, they always thought he would hit. And so some legitimate concern had begun to surround Ramos, who at age 31 seemed to be lacking his usual bat speed and extra-base punch.

To counteract that, Callaway and the Mets’ batting-practice pitchers recently began throwing Ramos more middle-in pitches before games, hoping to get him to pull the ball more and spark his power. They don’t expect otherworldly thump from Ramos, whose career high is 22 homers, but they do expect more than the one home run Ramos gave them in their first 39 games.

“You want him to pop one every now and again, and have a good approach and drive in runs,” Callaway said. “It’d be nice for him to be a power threat in there as well -- not just for the homer that you get, but for the intimidation factor of the other team.”

Winning in itself can be intimidating, and the Mets, with three straight victories and four in their last five games, are finally doing that with some consistency. Tuesday’s victory not only moved them back into a tie for second place in the National League East, 3 1/2 games behind the Phillies, it sunk the Nationals into an eight-game deficit in the division. And although it remains quite early for scoreboard watching, those numbers have the Mets in much better spirits than they were a week ago.

“It is nice to win some ballgames and see the fruits of your labor, because they’ve worked hard for it,” Callaway said. “We all felt like it was going to turn around, but when it’s not materializing, it can be tough. They gritted it out. … We have to continue to play the game the right way and get our hitting and our pitching synced up, and try to take off here.”