Steven Matz was a hit in more ways than one.

Before even throwing his first warm-up pitch — just half an hour into the fan shop being opened at Citi Field — every piece of memorabilia with the 24-year-old southpaw’s name on it was sold out.

“He came out of the bullpen and got a standing ovation — who gets that?” Matz’s Ward Melville High School head coach Lou Petrucci said. “New York has 100 guys that have gotten the hype, and how great is it that Steven Matz lived up to it? And he didn’t just live up to it, he exceeded it — and that’s what’s so great about this.”

But it may not have seemed that way from the start.

The first pitch Matz threw, a 96-mph fastball to the Cincinnati Reds’ Brandon Phillips, was wild, as it nicked catcher Johnny Monell’s glove and traveled to the warning track behind the plate.

In that same at-bat, Phillips hit a game-opening home run, and all Long Island fans could do was hold their breath and hope the local star, who had only made his Triple-A debut just one year ago, could turn things around. And he did.

Matz had finished his season 7-4 with a 2.19 ERA and 94 strikeouts over 90.1 innings for Triple-A Las Vegas, and he wasn’t going to sweat the small stuff.

After shaking off the opening at-bat jitters, the side was retired, and it was smooth sailing the rest of the way.

“A lot of people would have just cracked under the pressure, but that just ignites Steven’s fire,” former MLB pitcher Frank Viola, who pitched for the Mets from 1989-91, said in an interview with Seton Hall University’s radio station WSOU. “He’s more than just a baseball player — that’s secondary. He’s just a wonderful person, terrific kid; you root for people like that. The world needs more people like Steven Matz.”

The left-handed pitcher limited Cincinnati to two runs in the Mets 7-2 victory. The Reds’ second was another solo home run, this time off the bat of Todd Frazier. But Matz struck out both Phillips and Frazier in their next at-bats, and ended his 7.2 innings with a 2.35 ERA on five hits while striking out six and walking three.

What may have been even more impressive though, was his historic debut at the plate.

Everyone knew Matz could hit — he finished AAA with a .304 batting average, but no one could predict he would go 3-for-3. Just six innings in, the 999th player in Mets history found his way into the team record book by being the first player at any position on the team to have four RBIs in his MLB debut.

“It’s like a movie script,” Matz’s father, Ron of Stony Brook, said. “Aside from the home run in the first inning, where everyone was a little nervous, it was amazing the way he could shake it off and continue doing what he does. He’s always been a good hitter, but I never realized that at the major league level he’d be the star. He was a one-man show.”

Steven Matz has always had his own piece of fame since senior year of high school.

In the Three Village community, he had a sandwich named after him at the Se-Port Deli in East Setauket after being drafted by the Mets in 2009. But now, everyone across the Island has heard the 24-year-old’s name after he was called up to The Show last Thursday, making his official debut Sunday afternoon.

“I first got the phone call from Steve and he just said ‘Dad, I’m going to the big leagues,’” Ron Matz said. “I got pretty emotional. To see what he’s been through over the years, with the Tommy John surgery and all of that stuff and him battling back and doing what he did to finally get to the point where he is, it was a pretty proud moment.”

The father recalls his son’s younger years in the sport, and cannot believe how far he’s come to get to where he is today, although admitting he thinks it’s strange to see his name on everyone else’s back.

“Steve used to always come out with one of his older brother Jonathan’s uniforms on that would hang down past his feet,” Ron Matz said. “He was out there playing with the 5-year-olds when he was 2, and I always knew he had something special, and now everyone was rushing to the store once we heard there was a Matz jersey available. The line was out the door with people buying these things. His memorabilia was sold out within the first half hour.”

And everyone knew he had what it took to play in the big leagues.

“I’ve been coaching Steven since he was 9 years old, and when he was about 10, I told his father ‘Your son’s going to pitch in the big leagues one day,’” former MLB left-handed pitcher Neal Heaton said. “He thought I was full of it.”

But Petrucci saw it, too.

“He’s a complete baseball player, a complete athlete, terrific listener and he is extremely focused, and that’s what makes it so easy for him,” he said. “This kid is a product of all of the people who have touched him throughout the Three Village community: coaches, players, family members. How do you not root for this kid?”

Matz joined a young Mets rotation with the likes of Matt Harvey, Jacob DeGrom, Noah Syndergaard and the injured Zack Wheeler, which Mets manager Terry Collins said is a staff to be reckoned with.

“I think it sends a message to our fan base that the future is now,” he said in a press conference following Sunday’s game. “We’ve been talking about down the road, next year, next year; the future is now. They’re here, they’re going to pitch, and it’s going to be exciting to see them grow from start to start.”

Matz was also the first Mets pitcher with at least three hits and four RBIs since Dwight “Doc” Gooden in 1985, and Doc thought the way the southpaw handled himself on the mound after the opening pitch said a lot about his character.

“Giving up a home run to that first guy, it probably didn’t bother him as much as it would some other guys because of what he’s been through to get to that point,” he said. “That can go a long way in showing his character and mound presence when it comes to pitching against tough teams and big games come September.”

Matz’s former high school coach said he sees the pitcher going far.

“Every level Steve has gone up he’s only continued to get better because he’s more determined than ever and he’s dedicated to being the best pitcher that he can be,” Petrucci said. “Is he going to go 3-for-3? I don’t think so. But is he going to get his share of base hits? You bet he is. Will he win some games? Oh, you bet he is. The bigger the stakes for Steven Matz the higher he rises up to the occasion. This is more than just the beginning. This is the start of something special.”

Clayton Collier contributed reporting.