Mets relief pitcher Edwin Diaz throws during the 10th inning...

Mets relief pitcher Edwin Diaz throws during the 10th inning of the team's baseball game against the Reds on Wednesday in Cincinnati. Credit: AP/Jeff Dean

Is it safe yet to say the Mets won the Edwin Diaz trade?

That’s what we should be calling the 2018 deal with the Mariners. It started as the Robinson Cano swap and briefly transitioned to the Jarred Kelenic giveaway, but only now is former general manager Brodie Van Wagenen’s parting gift truly appreciated.

There are extenuating circumstances, of course. While Diaz again is one of the sport’s most dominant (and reliable) closers, it required Steve Cohen’s ownership to overcome Van Wagenen’s folly of absorbing Cano’s bloated contract.

Without Cohen’s magic eraser — the luxury of having a $15 billion fortune — the Mets likely don’t jettison Cano in May and eat the remaining $38 million on his contract. If Cano still was dragging down this roster, that would count against Diaz’s contributions.

But Cano is collecting his checks at Triple-A El Paso now, in Padres cold storage, and Diaz is shining on the Flushing stage, flashing more fastball velocity — 99 mph average, 102 max — than at any other point in his career. As for Kelenic, his can’t-miss label has peeled off some, and he’s currently at Triple-A Tacoma after two inconsistent stints with the Mariners in the past two seasons (.173 batting average, .594 OPS).

Kelenic is only 22, so he still has plenty of time to torment the Mets for sending him to Seattle. But Diaz is far more valuable to what Buck Showalter & Co. are trying to accomplish this season, with Cohen going all-in to beat his three-to-five-year estimate for bringing a World Series trophy back to Flushing.

And after what he’s done to this point, it’s getting easier to imagine Diaz saving big games in October. Before Thursday’s series opener with the Marlins, Diaz led all MLB relievers with 66 strikeouts and a 17.82 K/9 ratio. He was tied for fifth with 19 saves, and his 82 as a Met ranks ninth on the franchise list, one shy of Francisco Rodriguez, two short of Roger McDowell and four away from Tug McGraw.

Diaz also was named NL Reliever of the Month for June, and in the 15 games since his last blown save on May 24, he’s 8-for-8 in save chances with a 0.61 ERA, 32 strikeouts and only three walks in 14 2⁄3 innings.

“I know how hard it is to do what he’s doing and how it can get off course a little bit now and then,” Showalter said. “I saw him in Seattle when he just started closing and it was this guy. Edwin attacks . . . He just wants to win. He’s just like, that’s what I’m here to do. And I don’t think that’s going to change if he hits some bumps in the road.

“I think he’s come to grips with who he is and what he has to do to be successful. He also understands how fleeting it can be — not only in New York but anywhere. People get frustrated when you get that close to a win, that sense of finality. It’s a hard job, and that’s why they’re so coveted when you get somebody that can do it.”

Diaz has never done it better in a Mets uniform than right now. And there are two significant reasons for that. The extra fastball velo definitely helps. His 99.0 average ranks sixth in the majors and is the peak of a steady career climb, up from 98.8 last season, 97.8 in 2020 and 97.4 in 2019.

Diaz credits some mechanical tweaks as well as putting on 10 pounds of muscle during the winter, which explains the 102 max.

“I don’t try to throw hard, I just try to locate my pitches,” Diaz said. “Sometimes I pop 101 or 102, but I’m just trying to throw strikes. I don’t care as much about my velo because I know I throw hard. I care more about the location of my slider every time.”

As Diaz mentioned, the triple-digit heat is virtually worthless without putting it in the right spot. Otherwise, the pitch can leave the barrel even quicker than it comes in if Diaz grooves one down the middle of the plate, a problem he’s struggled with at times here (15 homers/58 innings in 2019). But deftly carving up the plate is a key improvement with him this year that’s caused his swing-and-miss rates to skyrocket. He’s getting whiffs on 51.7% of his sliders — as compared to 47.9 last season — and 35.2% of his four-seam fastballs, up significantly from 25.8% a year ago.

“This year I’ve been better at repeating my mechanics,” Diaz said. “That’s why I’ve been able to command my fastball better, my slider a lot better. That’s the reason why I’ve been so successful this year.”

He’s already earned the confidence of his first-year manager, and that should be enough to secure him an All-Star invite for later this month. The spotlight only gets brighter from there, but Diaz finally seems ready for it.