Jay Bruce stepped up to the plate in the fifth inning draped in the massive shadow of the man who came before him. The Mets had lost last year’s trade deadline savior, Yoenis Cespedes, to the disabled list Wednesday night, and here was Bruce, this year’s acquisition, who had inaugurated his Mets career with an 0-for-10.

It’s true that no one expects Bruce to come in and do what Cespedes did in the final two months last year — Bruce himself refuses to think that way — but with their erstwhile outfielder injured and an uncertain timetable for his return, the Mets do need something big from the former Red. And for one night, for one pivotal at-bat in a pivotal game against their crosstown rivals, Bruce showed it was possible.

With one mighty swing, Bruce — who was actually hitless in his previous 19 at-bats — did what the Mets’ front office envisioned when they brought him to Flushing on Monday. He hit with runners in scoring position (never discount that for this team, which came into the game hitting .204 with RISP) and he blasted his 26th home run of the season, a three-run shot, pacing the Mets to a 4-1 win over the Yankees at the Stadium and a Subway Series split.

“I told some guys that it felt like my first major-league home run running around the bases, so it was good,” he said. “It was good to make an impact that way and it ended up being a big spot.”

Bruce is unlike Cespedes in many ways and, he said, it’s pivotal to his success that he not try to be something he’s not. But there is one glaring similarity: When the Mets brought in both him and Cespedes, it was because they believed that their season wasn’t done. And now, partially because of Bruce, they’re one game out of the second wild-card spot — hardly ideal, but not disastrous.

“The atmosphere in that clubhouse the other day when we got Jay Bruce should have been our front office and our ownership don’t think that we’re dead, or they wouldn’t have gone out and did what they did,” Terry Collins said before the game.

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After the win, he added: “We’re very lucky to be where we are . . . You’re in this, and these games mean a lot.”

Bartolo Colon (10-6, 3.46 ERA), ever reliable, pitched 6 2/3 innings and allowed six hits and one earned run, on Aaron Hicks’ RBI single in the seventh off reliever Jerry Blevins, which drove in Gary Sanchez, who had doubled against Colon. He also became the first pitcher to win a Subway Series game for both the Yankees and the Mets, according to ESPN. He beat the Mets on July 2, 2011, in his only year as a Yankee.

The Yankees got the tying run to the plate with one out in the ninth against Jeurys Familia, but Rob Refsnyder grounded into a 5-5-3 double play to end the game to give Familia his 38th save.

The Mets got all their runs in that big fifth inning, and it started with Kelly Johnson, who hammered Nathan Eovaldi’s first-pitch cutter to the short porch in right — just into the first few rows — to lead off the inning and give the Mets a 1-0 advantage. Then, with one out and Curtis Granderson on second, Alejandro De Aza hit a comebacker to the mound. Eovaldi (9-8) tried to get Granderson, who had ranged off the base. Granderson, though, slid back to second before Didi Gregorius’ tag, and De Aza made it to first easily.

All of this, though, turned out to be background noise to Bruce’s real, official introduction to New York. Bruce took hold of Eovaldi’s 1-and-1 slider and gave it a ride, 385 feet to right-center for a 4-0 lead. It was his first homer since his torrid streak in late July, when he hit six in five games — a tear worthy of Cespedes himself.

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He also proved that though he can’t replace Cespedes in star-power, Jay Bruce, the power-hitting outfielder, is nothing to scoff at.

“I have to be myself,” he said. “The worst thing that I can do is try to be more or something else other than what I am . . . [Cespedes is] going to come back and he’s going to be healthy and be the force he always is and we have to play good baseball until then.”