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In a contest that featured a complete-game shutout from David Peterson, two home runs from Brandon Nimmo and a fifth home run in his past 11 games from Juan Soto, Pete Alonso might have been the quietest major contributor.

The Mets slugger just keeps hitting — and continues playing a better-than-the-numbers defensive first base — as a hot start has become a hot two-plus months of the season.

Alonso drilled an RBI double in the first inning to give the Mets the only run they would need and did his best in helping Peterson take down nine scoreless innings for the first time in his career in Wednesday’s 5-0 victory over the Nationals at Citi Field.

By jumping on a two-out curveball from Jake Irvin and one-hopping the center field wall to drive in Nimmo, Alonso extended his on-base streak to 19 games and hitting streak to eight games.

Over those eight games, he has gone 14-for-44 with eight extra-base hits, nine runs scored, 17 RBIs and a 1.470 OPS.

Overlooked defensively, Alonso made several clutch stops to help Peterson through a game in which any extra pitch would have been costly. In the second inning, Alonso made a nice scoop on a ball that third baseman Ronny Mauricio threw in the dirt.

With two runners on in the seventh, Alonso knocked down a ground ball from Alex Call, picked it up and won the foot race to the bag.

“The defense making some big plays, Pete knocking that ball down,” Peterson said. “I get the attention for it, but this was a huge team win.”

Jeff McNeil (1-for-4) extended his on-base streak to 14 games.

The Mets are open-minded — and perhaps unsure — about what they have in Paul Blackburn.

The righty started one game after coming off the injured list, throwing five scoreless innings at Dodger Stadium on June 2, and then was bumped from a starting group that had been excellent while he was rehabbing his knee injury.

Blackburn was shuffled to the bullpen and able to remain stretched out by eating up four innings on 71 pitches Sunday, when he earned the rare blowout save by mopping up a game that had been decided early.

Asked if Blackburn would remain in that piggyback role, Carlos Mendoza said, “not necessarily.”

“It happened that day [in Colorado] — we were staying away from a lot of guys [in the bullpen] that day,” Mendoza said. “But if we need to use him for an inning or two in high leverage, we would do it.

“We feel good with him fully built up, and we can get 75 to 80 pitches there. But if we need to shoot him there for a couple of innings, we will, too.”

Blackburn made just his fifth career relief appearance, while he has started 83 games. He has taken the reduced role willingly.

The Mets traded for the 31-year-old at last year’s trade deadline, but his time with the club has been marked by a series of injuries.

Mark Vientos again took swings in the batting cage and jogged in the outfield.

The third baseman, who has been out since June 2 with a right hamstring strain, does not look far from a rehab assignment.

Several around the Mets, including some coaches, wore shirts that read, “Vote Mets” as an All-Star push.