NEW YORK -- No. 8 hitters bat eighth for a reason. They are generally not the best hitters in a lineup, nor the most powerful. Sometimes they are defensive experts. Sometimes they are backups.

 They rarely, in other words, accomplish the type of thing that Mets catcher Tomás Nido did on Thursday, hitting his first career grand slam as part of a multihomer, six-RBI game in an 8-2 win over the Nationals. Nido became just the third Mets hitter to drive in at least six runs from the eight-hole in the lineup, joining Dick Schofield in 1992 and Paul Lo Duca in 2007.

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“To be honest, hard work pays off,” Nido said. “I did work really hard this offseason, and it just feels really good to help the team win. It’s not about myself. At the end of the day, no matter what I do, if I don’t help the team win, that stings a little more than if I do good and we lose. So I’m very happy to be able to get that ‘W.’”

With manager Luis Rojas giving Wilson Ramos a routine day off following a night game on Wednesday, Nido started behind the plate for the matinee at Citi Field. He made his initial impact in the fourth inning, hitting a go-ahead two-run homer to give the Mets a lead they would never relinquish.

An inning later, Nido completed his first career multihomer game with a grand slam off Nationals prospect Seth Romero, who was making his Major League debut. The feat felt even more significant, Nido said, because of his throwing error in the first inning, which helped ignite a Washington rally. The Nats only scored one run thanks to Jeff McNeil, who bruised his knee crashing into the left-field fence while making a run-saving catch and had to be carted off the field. But Nido stewed over his mistake nonetheless.

The grand slam did wonders to lift his mood.

“It felt really good,” he said, “especially after the way the game started. I had a little pressure on myself, so I’m glad I was able to pick the team up and get them back for that error at the beginning.”

Historically a light-hitting backup catcher, Nido batted just .191 last season and, by year’s end, was regularly ceding at-bats to veteran René Rivera. Nido entered Spring Training out of Minor League options, prompting the Mets to commit to him as a backup despite his middling performance.

By that point, however, Nido had spent an entire offseason reworking his swing, cleaning up “a lot of things that obviously weren’t working last year.” The early results have been solid. In limited time as Ramos’ backup, Nido is batting .353 with three extra-base hits.

“He’s been better this season,” Rojas said. “I know he worked in the offseason a lot with his approach, and he’s been better with his approach. He’s been walking more. He’s been able to run into pitches like that because that’s what’s going to happen when he can lay off some others. … Six RBIs, it’s a big day for him.”

Peterson sore, but unworried

Rookie starter David Peterson departed after five innings and 74 pitches in part because of what he called “typical” soreness in his left shoulder. He dismissed any concern over the issue, however, and expects to be completely fine moving forward.

“I did not want to come out of the game, honestly,” Peterson said. “I felt good against that lineup. But we also have another month and a half of the season, so we’ve got to be careful.

A regular member of the rotation with Noah Syndergaard sidelined and Marcus Stroman electing not to play, Peterson has yet to throw more than 87 pitches in any of his four starts. He also hasn’t lasted more than six innings in a start, as the Mets look to maintain his current level of success: a 3-1 record and 2.91 ERA. Peterson became the third Mets pitcher to start and win three of his first four career games, joining Jason Jacome in 1994 and Steven Matz in 2015.

“We played it safe,” Rojas said. “We still have a lot of games to go. This kid is throwing the ball well. So nothing serious.”

Committing to Amed

Shortstop Amed Rosario initially began suffering the effects of a stomach bug on Monday. Despite spending the next two-plus days hydrating, he has been unable to make it back to the lineup.

That Rosario has missed three straight games at a time when fellow infielders Andrés Giménez and Luis Guillorme are playing well is a coincidence, Rojas insisted on Wednesday. As soon as Rosario is ready to play again, he will be back in the lineup, supplanting Giménez at shortstop.

“Rosario is our shortstop,” Rojas said. “We’re waiting for him to be ready to go, and then he’ll be back in there.”