In his first spring start as the Mets’ Opening Day starter, Clay Holmes showed promise with 4 ¹/₃ innings of play against the Nationals at CACTI Park of the Palm Beaches in a 4-1 loss. This was a significant step as he aims to reach his target of around 90 pitches by the start of the season.

This outing marked the first time Holmes experienced some fatigue in his new role. He noted the importance of pitching through this fatigue, emphasizing the necessity to make crucial pitches once the pitch count climbs above 70. Despite the challenges posed by tiredness, Holmes recognized the value of pushing through and testing how his body responded.

He’ll likely pitch with an extra day’s rest in his final Grapefruit League start leading up to his March 27 assignment in Houston.

Reflecting on the increased workload, Holmes expressed satisfaction with the experience, stating, “It was good to feel that. It was good to pitch through it and see how your arms and legs feel. Once you get above 70 pitches, anybody, you’ve got to make pitches. Hitters have seen you and you’re a little tired, but those pitches are important.” This resilience and determination will be key for Holmes as he continues to prepare for the upcoming season.

It’s the next step in the process for the ex-reliever, whose transition to the rotation with the Mets has been without a misstep so far.

“It’s all new for him, especially when he gets to that territory,’’ manager Carlos Mendoza said of the added workload. “That’s what he’s gonna have to get used to. … Finding a way to make pitches to get people out. We feel he’s equipped to handle it.”

Jesse Winker started in left field, as the Mets look for depth in that aspect of their roster — especially with Brandon Nimmo still limited by right knee soreness.

Mendoza said Winker is “preparing” to play the outfield during the regular season after starting in both corner outfield spots with both Washington and the Mets last season.

“We’ll see how it plays out,’’ Mendoza said of whether Winker would be used there again after the addition of Juan Soto in right field and defensive specialist Jose Siri.

Winker will certainly be called upon to DH against right-handers, as the lefty-swinging Winker could platoon with Starling Marte.

Marte is still coming back from knee soreness and has yet to play defense, although Mendoza said that should change before the end of spring training — perhaps as soon as Wednesday.

“The goal is to get him in the outfield before we break camp,” the manager said. “He continues to feel good.”

Asked pregame if anything was “new,” Mendoza said, “Nothing new. That’s a good thing.”

It meant there were no additional injuries to report during a camp that’s been filled with them.

And at least so far, the Mets have gotten encouraging results from a pair of pitchers who have dealt with their fair share of injury woes in recent years, as Edwin Díaz “felt good” and hit 97 mph during a minor league game in Port St. Lucie. Ryne Stanek and left-hander Danny Young also appeared in the game.

And Mendoza also said Kodai Senga felt good following his Friday night start, bringing him a step closer to beginning the season in solid form.

Mark Vientos was not among the players to make the trip to play the Nationals on Saturday in what has been a drama-free camp for a player who emerged as a key part of the lineup last season.

Mendoza said Vientos is “more mature” than at this point a year ago from a baseball standpoint.

“Last year, he was competing and battling [for a spot],’’ Mendoza said. “As a player, it’s a better feeling to know you’re on a team and can work on offense, defense and baserunning. That’s what he’s doing now.”

And it’s paying off.

“I see a guy who’s comfortable,” the manager said. “He had success in the regular season and the playoffs. That means a lot.”