Mets starting pitcher Jacob Barnes throws during the first inning...

Mets starting pitcher Jacob Barnes throws during the first inning of a spring training game against the Astros on Saturday in Port St. Lucie, Fla. Credit: AP / Lynne Sladky

PORT ST. LUCIE, Fla. — Don’t pencil it in just yet for the fifth game of the season, but the Mets’ trial run of using an opener on Saturday got thumbs-up all around, from reliever-turned-opener Jacob Barnes, from starter-turned-long-reliever Joey Lucchesi and from manager Luis Rojas.

"That went really well," Rojas said after the Mets beat the Astros, 8-3. "There’s just a lot of good things that happened here today."

Barnes began the exhibition game with a perfect first inning against Astros first-stringers Jose Altuve (strikeout looking), Michael Brantley (groundout to second) and Alex Bregman (strikeout looking).

Lucchesi entered in the second and pitched 4 2/3 innings, allowing one run and three hits. The only blemish was a home run by Bregman, his final batter. He walked one and struck out four.

That is basically how the Mets wanted the opener/starter sequence to work.

"Just took it as a start," Lucchesi said. "Told myself, ‘Stay locked in, I got work to do.’ I actually felt really great today. I didn’t mind it, I guess. Can’t control it."

Would he be comfortable pitching this way in a regular-season game?

"I’ll do whatever they tell me," Lucchesi said. "I like starting. If they want to do an opener, they can do that. I’m just out there to pitch and do my best to help us win ballgames. I just love pitching, man. I just love to be out on that field."

Barnes, for his part, seemed to enjoy it. The only strangeness stemmed from having so much time to warmup and knowing exactly when he would pitch, he said. Usually, he gets a batter or two in a pinch. As the opener, he had hours. Next time, if there is a next time, he might wait longer to begin his pre-appearance routine, he noted.

"Now that I’ve just done it, I’m very comfortable with it," Barnes said. "It’s definitely something that’s kind of trending in the game so you kind of have to get used to it."

A primary candidate to win a bullpen job, Barnes is up to five consecutive scoreless Grapefruit League innings, allowing two hits and striking out eight (with no walks) in that stretch.

Among the risks of using an opener is putting both pitchers in situations with which they are not familiar. For Lucchesi, like Barnes, that proved not to be a problem. Lucchesi went through his same pregame procedure, just a little later than normal.

"I didn’t change," he said. "Did everything the same, got my long toss in, got all my [stretching] bands, same thing, did everything the same, pushed it a little bit, 10-15 minutes back. I was set up perfectly to come in the game."

This experiment was one of the final pieces of data the Mets sought before deciding on a fifth starter.

Lucchesi likely is the choice for that gig, and he finishes his spring-training audition with a 2.77 ERA in four games. He had 15 strikeouts and four walks.

Now the Mets want to give lefthander Mike Montgomery one more shot, a start Sunday against the Marlins in Jupiter. He is in camp on a minor-league contract and the Mets say he still might make the rotation. If not, perhaps the bullpen.

"He’s also competing for being on our roster, because he’s done both," Rojas said.

If the Mets go with Lucchesi, they can do so knowing that pairing him with an opener is something comfortable for all involved.

"It went terrific," Rojas said. "Let’s keep watching what happens the next two days. [On Sunday] we have Montgomery going. But that was nice to see."