Marcus Stroman was prepared to pick up the loss in his home debut. Then, the Long Islander found himself gleefully sprinting through the Citi Field clubhouse in his boxers, having watched Todd Frazier hit the game-tying three-run home run, which led to the Mets’ improbable 7-6 win over the Nationals on Friday night.

Stroman, who settled for his second no-decision in as many starts with the Mets, had pitched better on many occasions.

But rarely had baseball felt better.

“I can’t put it into words. I want to pitch [in] every single game like that,” Stroman said. “It felt, honestly, like a playoff atmosphere, like that [World Baseball Classic] atmosphere that I had, from the second I walked out there. The entire crowd was going crazy. I love energy. I love that. Keep bringing that energy New York. We’re gonna feed off of that.”

With friends and family watching from the crowd, Stroman opened looking like the ace who made his first All-Star team this season. Through three innings, the groundball pitcher had compiled seven strikeouts — including five consecutive strikeouts for the first time in his career — matching Washington’s Stephen Strasburg zero for zero.

Stroman, who lasted just 4 ¹/₃ innings in his Mets debut at Pittsburgh, struggled in the fourth, allowing a leadoff single to Adam Eaton, followed by a Trea Turner triple and a Juan Soto home run that put the Nationals up 3-0. The Mets evened the score in the bottom of the inning, then saved Stroman from great damage.

With runners at the corners and no outs in the sixth, Stroman induced a groundball from Kurt Suzuki, forcing Soto out at home. Amed Rosario followed by robbing Brian Dozier on a high line drive. Stroman finished the frame, striking out Strasburg with the bases loaded, as Queens erupted, and the right-hander ran back to the home dugout, pounding his glove, screaming to the crowd.

“He battles. Here’s no doubt about it. This kid is gonna battle and you’re gonna have to beat him. That’s what you want out of every guy on your team,” manager Mickey Callaway said. “There is no doubt that Marcus Stroman has that type of personality.”

Stroman was removed after walking the leadoff hitter in the seventh, then watched as Justin Wilson gave up a two-run homer to Anthony Rendon. Stroman allowed four runs and nine hits in six-plus innings, with three walks and a season-high nine strikeouts.

Sporting a Darryl Strawberry jersey in front of his new locker, Stroman could only smile. The day didn’t go as he envisioned. It went even better.

“It was amazing. That crowd brought it,” Stroman said. “I’m extremely grateful to have their presence there, their energy. I don’t think they realize how much we feed off of that, and how much that gets us going and allows us to elevate our game when we need to.

“I’m just happy to be here. And it’s a great vibe that we have on this team.”