The Mets' Jacob deGrom looks on during a spring training...

The Mets' Jacob deGrom looks on during a spring training game against the Astros at The Ballpark of the Palm Beaches in West Palm Beach, Fla., Saturday. Credit: Newsday/Alejandra Villa Loarca

WEST PALM BEACH, Fla. — In what has become an annual rite of spring training, the obvious became official Saturday with an acknowledgment from Mets manager Luis Rojas: Jacob deGrom will start on Opening Day, April 1, against the Nationals.

"You can call it an easy decision," Rojas said.

This will be the third time in his career and the third year in a row that deGrom gets the ball for the season opener. He is the first Mets pitcher to do that since Johan Santana (2008-10). The only hurlers with longer streaks in the franchise’s history are Dwight Gooden (four in a row from 1988-91) and Tom Seaver (10 straight, 1968-77).

Being mentioned alongside those names isn’t new for deGrom, but it still makes him smile.

"Any time that you get the nod for Opening Day, it’s a huge honor," he said. "Every time I’m mentioned with those guys, it’s an honor as well."

His road to the regular season reached a milestone Saturday with his Grapefruit League debut, two scoreless innings in a 6-1, six-inning win over the Astros in which he touched 100 mph with his fastball. He worked around a walk in the first inning and a double in the second, struck out three (all in the second inning) and threw 29 pitches.

After having trouble with his secondary pitches and fastball location during the opening inning, deGrom and catcher James McCann decided he should stick with the fastball. On his three strikeouts, he threw 13 pitches, all of them fastballs that clocked at 99 mph, according to the radar gun at The Ballpark of the Palm Beaches.

"In the first inning, I was sailing some fastballs high," deGrom said. "Then that last inning, I was really trying to see the glove and hit it."

Said Rojas, "A good two innings for him, and he got to a comfortable pitch count that we wanted. So it was a productive day."

That made Saturday more successful than deGrom’s spring training soft opening, a live batting practice session on Monday that included an impromptu showdown with Michael Conforto.

When deGrom looked at the list of hitters he would face and saw that Conforto, who turned 28 that day, wasn’t on it, he chided him about wanting to take his birthday off. Conforto told deGrom he wasn’t afraid, though he admitted Saturday that in a half-decade of facing the Mets’ ace in such a setting, he had maybe one hit against him, a single last year.

"That’s why he wanted me in there," Conforto said. "Boost his confidence a little bit."

This time, not so much. After striking out and grounding out, Conforto homered in his third at-bat.

"I started jogging back to the clubhouse as a joke, basically saying, ‘I’m done. I’ll take 1-for-3 off deGrom,’ " Conforto said. "So I took all my stuff off. I sat down. As he was still going, he’s getting close to his pitch count, he called me out there again and said, ‘You’re not done. You’re going to face me one more time.’ "

Another long ball ensued.

"There was some discrepancy over whether or not I walked," Conforto said. "He wouldn’t let me walk. I thought I walked. Maybe I got the count wrong in my favor. That next pitch, I ended up hitting a slider [over the fence]."

"He gave me a little humble pie there," deGrom said.

He won’t have to worry about facing Conforto on Opening Day.

"He’s our No. 1 guy," Rojas said. "Everybody knows."