OAKLAND -- From the time Luis Medina walked into the A’s clubhouse on Tuesday afternoon, catcher Shea Langeliers sensed a unique energy about him. As the two sat down to go over scouting reports, he noticed the vibe was especially unflappable, even for Medina, who carries a strong belief system each time he takes the mound.

“You could just feel it,” Langeliers said. “There was a different mentality from him. He was just locked in the whole day. I could just feel it. Warming up and watching him play catch to the beginning of the game, he kind of had that extra swag today.”

Medina certainly took his lumps in the first half of the season. Through the first 12 games (eight starts) of his Major League career, the 24-year-old rookie’s 6.34 ERA ranked eighth worst out of 79 American League pitchers with at least 50 innings pitched.

Still, both Medina and the A’s remained unfazed by the rough beginning. They know what type of talent exists within that electric right arm of his. The skill was evident in Tuesday’s 3-0 victory over the Red Sox at the Coliseum, snapping Oakland’s eight-game losing streak.

Making his first start back from the All-Star break, Medina's fastball that maxed out at 100 mph in the first inning set the tone as the right-hander turned in his first scoreless outing as a big leaguer by limiting Boston’s offense to just three hits and a walk with six strikeouts over 5 2/3 innings.

Prior to Tuesday’s contest, A’s manager Mark Kotsay discussed the growth that the club was looking to see from Medina in the second half. His high velocity is a well-documented attribute, but taking that next step requires more than overpowering stuff.

“Even though he throws hard at 97-98 mph, execution of the breaking ball and mixing of speeds is part of that success that’s going to make him even better,” Kotsay said. “When he understands that and is able to use his other pitches in the zone, I think he’s going to take a step forward. … We’re hopeful that Medina can take that step. It may take longer, but we definitely feel like there is a path to success for him.”

On Tuesday night, the usually fastball-heavy Medina showed that sign of growth by distributing all five of his pitches about as evenly as he ever has in a single start. According to Statcast, Medina’s sinker was his most-thrown pitch at only 27 offerings. He also threw 21 four-seam fastballs, 15 sliders, 14 curveballs and three changeups. More importantly, Medina consistently succeeded in landing all five pitches in the zone, with 53 of his 80 pitches going for strikes.

“Long term, when he starts doing this consistently, it’s going to be seven, eight innings, even complete-game shutouts,” Langeliers said. “That’s what he’s capable of. He’s special. He’s going to build off this. That mentality he had tonight, he’s going to keep coming back with it, and it’s going to be fun to watch.”

An example of Medina’s filth was on display in the first at-bat of the game. Facing Jarren Duran, Medina fired a 1-2 fastball at 100 mph that was just fouled off. One pitch later, Medina came back with an 84.1 mph curveball that produced an off-balance swing from Duran for strike three.

“It’s way more fun to catch it than it is to try to hit it,” Langeliers said with a laugh. “How much the curveball moves and the speed difference, then coming back with 100 mph, and he’s got a four-seam and a sinker, so you don’t know if it’s going to go straight or going to run in on your hands. It’s just tough. … The sky’s the limit for him.”

Making Tuesday’s outing perhaps even more impressive was the fact that the Red Sox already had an idea of what to expect from Medina, whose final start before the All-Star break also came against them at Fenway Park. That day, Medina racked up a career-high nine strikeouts.

“His arsenal’s kind of evolving and changing, and he’s figuring out the pitcher he wants to be,” Red Sox left fielder Rob Refsnyder said of Medina. “He’s got really, really good stuff. He kept us off-balance with some fastballs away, fastballs up, sinkers in and then multiple breaking balls.”

Medina’s goals for the second half are team-centric, with a focus on doing what he can to help the team win more games after a miserable first half. Beyond 2023, though, exists a bigger goal he’d like to reach.

“My No. 1 goal is to be a No. 1 pitcher for this team,” Medina said. “I’m going to get there in time. It’s all about just staying patient and waiting for it.”