Steven Matz finished his spring on a high note, but that late success didn’t translate into his first start of the regular season.

On Sunday, the left-hander labored through a ton of pitches, lacked conviction and placement and his velocity was nothing to write home about.

“The main thing was, maybe I was trying to do a little too much out there,” said Matz, who gave up three runs and four hits while walking three and striking out four. “I was really smooth and easy before the game. I was really feeling confident going in there. Then, when a hitter steps in, I try to make my pitches better. And that’s when I get in trouble.”

The 26-year-old started the day one the right foot by punching out Dexter Fowler, but then issued two walks.

He was able to escape the inning unscathed, but Paul DeJong made him pay in the second when Matz left a ball over the plate that was smacked off the facing of the deck in left field.

In the third inning, Marcell Ozuna who had gone hitless in his first two games as a St. Louis Cardinal drove in the second run of the game for the Red Birds with a double in the second.

Yadier Molina launched his second homer of the season in the fourth, Matz’s final frame.

When all was said and done, the southpaw threw 89 pitches in his first start since Aug. 17.

“He just couldn’t get the ball over the plate consistently,” Manager Mickey Callaway said of Matz. “Really deep counts, falling behind, things like that. It didn’t look like he had the confidence to throw it over.”

Matz fell behind eight of the 18 hitters he faced, but it was on two strikes where the most damage was done. DeJong’s homer, Ozuna’s double and Molina’s homer all came when he just needed one pitch to put them away.

“[The] fastball was just up,” Callaway said. “Up, up, up. Waist-high the whole time.”

“Yeah, definitely,” Matz said in agreement. “That’s where it starts for me. I was leaving the ball up a lot and I was giving them a chance to get their barrels to it. That’s really what I’ve got to be better at.”

Beyond Jacob deGrom and Noah Syndergaard, the rotation is still very much a question mark.

Matt Harvey, who also finished his spring on a positive note, will get the ball Monday and will look to get the Mets back into the win column.

As for Matz, hopefully he can rebound and pitch like the hurler we saw in his last four spring games where his ERA was under two, not the pitcher we saw Sunday.