If his first outing is any indication, the Oakland Athletics’ Nathan Patterson signing wasn’t just a publicity stunt.

The 23-year-old fan who earned a contract after hitting 96 mph during a ballpark speed-pitch challenge struck out the side in the first inning in his professional debut Thursday in the Arizona League, a rookie-level league in the minors.

“Last night was incredible and truly a blessing as I made my first professional outing,” Patterson wrote Friday on Instagram. “I’m not gonna lie, the nerves were flowing until I threw strike one. After that, I took a big deep [breath] and realized all the hard work over the last year has prepared me for this moment.”

Patterson’s debut came two weeks after signing with the A’s and about a month after he created a buzz on social media with a video in which he hit 96 on a throw at a Colorado Rockies game. Patterson didn’t play college ball, but played in high school.

“I still have a long ways to go and I love that aspect of this journey,” Patterson wrote. “It takes discipline, focus, and consistency day in and day out to be able to compete in professional baseball.”

The video from last month, posted by Patterson’s brother Christian, has been viewed nearly 2.5 million times.