It’s something that has been obvious all season, but Marlins manager Don Mattingly actually acknowledged the fact for the first time on Wednesday during his pregame media session.

Mattingly noted that Pablo López has assumed the role of de facto ace since Sandy Alcantara has been on the injured list. Even if Alcantara were on the active roster, López still is performing at a top-of-the-rotation level.

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Matched up against Jacob deGrom, López hurled 6 1/3 innings, allowing two runs with five strikeouts, and he kept Miami in the game. But after the Marlins pulled even in the eighth inning, Michael Conforto belted a two-run homer in the ninth off Brandon Kintzler to give the Mets a 5-3 victory at Marlins Park.

“It's just important that during this stretch that we hang in there,” Mattingly said. “But Pablo is becoming our guy. At this point, where our staff is right now, this guy is the ace of our staff. He's our best guy. You can count on him every time out, so far.”

The Marlins (9-9) have dropped a season-high five straight, and they are looking to avoid a four-game series sweep on Thursday.

The final outcome didn’t go the Marlins’ way, but López has reinforced the organization’s belief that he can be a front-line starter. Through his first four starts, the right-hander is 2-1 with a 2.42 ERA and 24 strikeouts in 22 1/3 innings with a 1.16 WHIP.

On Wednesday, he closely matched deGrom, the two-time reigning National League Cy Young Award winner. In six shutout innings, deGrom struck out seven. López’s season line is not far off from deGrom’s: 1.93 ERA and 35 strikeouts in 28 innings with a 0.89 WHIP through five starts.

Going pitch for pitch against the best is a good measure of how far López has come in his third big league season.

“From tonight, it's just competing,” López said. “We were facing one of the best guys in the league, and we were right there the whole time. We didn't take any out, any pitch for granted. We were out there competing. Eventually, if we keep doing the right thing, results are going to come.”

The Marlins erased a two-run deficit in the eighth when Eddy Alvarez was hit by a pitch from Dellin Betances with the bases loaded, and Edwin Díaz walked Logan Forsythe to bring in the tying run.

But in the ninth inning, Kintzler gave up a two-out single to Brandon Nimmo, and on a 2-1 pitch, Conforto crushed a two-run homer on a sinker that didn’t sink.

“Sinker stayed straight,” Kintzler said. “Dead sinkers get crushed. That's just what happened.”

The Marlins currently have three starters on the injured list -- Alcantara, Caleb Smith and José Ureña. In their absence, López has continued his rapid progression.

At 81 pitches through six innings, López came out for the seventh, but he surrendered a leadoff double to Dominic Smith. Two batters later, Luis Guillorme laced an RBI single to right, producing the Mets’ second run and ending López’s night at 90 pitches.

López effectively mixed up his pitch selection from when he last faced the Mets on Aug. 9 at New York.

On Wednesday, he threw 26 sinkers, 24 changeups, 23 four-seam fastballs and a few cutters and curveballs, according to Statcast. At Citi Field 10 days ago, he went with 31 four-seamers, 23 changeups and 18 sinkers as his three primary pitches.

“You always have to be ready for anything,” López said. “Maybe they were seeing pitches better this time around. So you just have to make sure you have your other weapons ready to use.”

Catcher Francisco Cervelli played a big part in guiding López’s pitch sequencing.

“I think Pablo continues to show the consistency that you talk about when you get your right starters out there, that you know have that type of quality,” Mattingly said. “As he starts to work himself into one of the guys that you know you can count on, every time he pitches, you know it's going to be five, six, seven innings. Once it gets there consistently, then you know you've got a dude.”