Edwin Diaz began the ninth inning with echoes of 2018. He overpowered and overwhelmed Logan Morrison with 91 mph sliders and triple-digit heat.

Confrontations such as this one on Friday night tease and elevate the Mets. Maybe this is the beginning of a Diaz return to last season when he was the game’s best reliever. It would be late, but perhaps not too late to still contribute to a long-shot run into October.

But then 2019 returned. Overpower and overwhelm quickly became over … done. A Jean Segura single followed Morrison’s futile strikeout and then J.T. Realmuto clobbered a slider for a game-tying, two-run homer. With the ball still in the air, Diaz raised his arms in exasperation. The Citi Field crowd — seduced by the Morrison strikeout — returned to the most familiar Flushing sound for Diaz this season. Boos.

The Mets ultimately survived more Diaz malfeasance because the injury-ravaged Phillies bullpen is worse — the last stop for those waived and designated for assignment. Pete Alonso drew a bases-loaded walk in the bottom of the ninth that gave the Mets a 5-4 triumph, tied the Phillies in the standings (at 72-68) and left them both four back of the second wild card.

Yet, whatever meager chance the Mets possess rests to a large degree on the duo most responsible for making them long shots — Diaz and Jeurys Familia. Had that duo just been competent, the Mets probably would be in playoff position with three weeks left.

Instead, Diaz and Familia have been historically bad. It has been 15 years (since the 2004 Rockies with Shawn Chacon and Javier Lopez) that a team had two relievers appear in at least 55 games each with ERAs 25 percent or more worse than MLB average factoring league and park. That Diaz has appeared in 59 games and Familia 55 reflects just how beholden the Mets are to the duo.

Even after Diaz’s seventh blown save, Mickey Callaway said, “If he can’t get the job done, we can’t get the job done.”

Diaz was asked to close because the workload has just been too onerous lately for Seth Lugo. Luis Avilan and Justin Wilson had again been good in support, and Brad Brach returned from more than a week missed to a shoulder ailment to deliver four maybe-he-can-help outs. But for the Mets to close, say, 16-6, then Diaz, Familia or most likely both will have to provide positive endings to negative seasons — which concurrently would offer 2020 hope.

Because what will next year’s pen look like? Lugo and Wilson have fragility about them. Avilan and Brach will be free agents. Robert Gsellman is a relief roller-coaster. Nothing special is percolating in the minors. Free agency is difficult unless Mets ownership is willing to greatly expand the payroll.

Before saying “just trade Diaz and Familia,” the questions should be: Who wants them and for what? Do you want to deal talented guys at the nadir of their value?

“Clearly bullpen will be a focus of ours in the offseason,” general manager Brodie Van Wagenen said. “So it is in our best interest to keep working with [Diaz and Familia] to get back to their best form. And we have confidence we can do that.”

The Mets believe Diaz’s slider has improved since Phil Regan became pitching coach in late June. Diaz has struck out 38.5 percent of those faced, sixth best among relievers. But he has yielded 2.42 homers per nine innings, by far the most in Met history for a reliever — Josh Smoker was at 1.60 in 2017. The ninth inning Friday was three strikeouts surrounding a single and homer, moving Callaway to call it “uncanny” how stuff good enough to dominate also is susceptible enough to doom.

Had there been a 10th inning, Callaway was planning to bypass Familia for Paul Sewald, noting Sewald’s control. Familia is averaging 7.53 walks per nine innings — the Mets’ relief worst had been 6.52 by Ryota Igarashi in 2011 (minimum 40 games).

Van Wagenen said he “believed in the makeup of [Diaz and Familia]” in disputing that this is a New York thing and they need to change locale. Van Wagenen is invested in the twosome because, well, he invested in the twosome. He traded two of his best prospects and took on the final five years of Robinson Cano’s pact to gain access to Diaz. And the Mets reunited with Familia for three years at $30 million.

He cannot get close to what he surrendered for Diaz in a trade and would have to eat money or absorb a bad contract to deal Familia. But that is for the offseason. There is still a slim postseason opportunity, a chance for this dud duo to save their season and that of the Mets.

But results like Diaz’s on Friday remind us how unlikely that is.

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