WASHINGTON — To make a wild run and jump over the Cubs and three other teams, the Mets are going to need plenty of energy this last month of the regular season.

That is where Brandon Nimmo comes into play.

Nimmo supplied a good deal of offensive energy in the Mets’ 7-3 win over the Nationals on Labor Day at Nationals Park. He set the tone with a 10-pitch walk against Joe Ross in a two-run second inning when he nearly ran down J.D. Davis from behind on Joe Panik’s run-scoring double. He eventually came around to score on Rene Rivera’s single to right. Nimmo walked the next inning, too.

Then in the five-run fourth, Nimmo’s RBI double against reliever Austin Voth, which followed Jeff McNeil’s two-run home run and Davis’ two-run double, made it a much easier work day for this excellent version of Noah Syndergaard.

Nimmo is one giant dose of 5-hour Energy.

The Mets did not get to their hotel until around 2 in the morning Monday after Sunday night’s difficult 5-2 loss in Philadelphia, their seventh loss in 10 games. They could not afford a loss to Ross, of all pitchers, with Max Scherzer facing off against Jacob deGrom on Tuesday night.

“He’s the king of on-base,’’ Michael Conforto told The Post of Nimmo, who owns a .384 lifetime on-base percentage.

If the Mets can somehow get the second wild-card spot, it will most likely be Scherzer against deGrom facing off here in the NL wild-card game.

The Mets have much work to do and need every ounce of energy they can get from Nimmo, who was activated Sunday after being out since May 21 with a neck injury. He drew a pinch-hit walk Sunday night and scored the tying run in the eighth, then came another Jeurys Familia meltdown.

So after not playing in more than three months, Nimmo reached base his first four plate appearances and scored three runs. He’s taking pitches when he has to and swinging at first-pitch meatballs when it is to his advantage.

“The at-bats are unbelievable,’’ Mickey Callaway said. “To not have been in a major league game for as long as he was and to walk and get hits like he has done the last two days is unbelievable.’’

Has Nimmo ever taken a 5-hour Energy drink?

“No, but I do recall in the South Atlantic League having to take a Monster Energy drink before a game,’’ Nimmo said. “I was pretty wired for that one, tingling. That’s the only time.

“Just to be back and being to help them is special, really big for me,’’ Nimmo said. “I’ve been watching from the outside and really miss them. I was real excited to bring a few things to the table. You know me I will try to bring as much energy as I can and I just want to be a positive force around these guys. To be able to contribute right away was really big for me. It took a load off my shoulders.’’

Said hitting coach Chili Davis, “Impressive. I thought he took good swings today, hitting the ball down the line and another into the outfield, I was pleased to see that.’’

Never forget ballplayers are human. They have their self-doubts, no matter how talented they are. They need positive reinforcement.

“I like to think that is one of the abilities I have is to know the strike zone,’’ Nimmo said. “My whole goal in coming to this was to contribute.’’

There is just more energy in the room with Nimmo. He is the co-worker who never is down, always has a smile and is fun to be around.

Conforto sometimes signals the safe sign when Nimmo races to first after he draws a walk.

“He beat another one out,’’ Conforto said with a smile.

Nimmo was so hyped Monday he nearly ran up the back of Davis at third base on Panik’s double.

“I wanted to be right on his heels so if he scored, I was going to score,’’ Nimmo said with a smile. “But I could see [third base coach Gary Disarcini] like trying to hold me up and trying to send him at the same time.’’

The Nimmo Effect in wild horse action.

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