Now, halfway through his first season at Double-A, the 23-year-old right-hander hasn't changed his opinion.
The Angels' No. 15 prospect struck out seven over six innings and combined with two relievers on a one-hitter Saturday as Arkansas blanked Northwest Arkansas, 4-0.
"I felt good out there," Pena said through a translator. "I was just trying to attack the strike zone with all of my pitches and hopefully get the defense behind me some work. Then the bullpen came in and did a good job of closing the door, so it was a good night."
After Yem Prades reached on an error and moved up on a bunt in the first inning, Pena -- who employs a mid-90s fastball and a plus slider -- struck out four Naturals in a row. He hung a 1-2 slider over the middle to Nick Van Stratten, who hit a liner up the middle for a single. It turned out to be the only hit of the night for the Royals' Texas League affiliate.
"I don't regret it at all," Pena said. "It was just one hit and you never know how the rest of the game will go. Tonight, everything else worked out."
Alex McClure walked and a wild pitch put two runners in scoring position, but Pena got out of the second inning by retiring Julio Rodriguez on a grounder to third.
The native of the Dominican Republic retired 12 of his final 13 batters, working perfect frames in the third, fifth and sixth. Mario Lisson's free pass in the fourth was the lone baserunners during that stretch.
Caleb Graham retired all six batters he faced and Kevin Johnson pitched a 1-2-3 ninth to finish off the Travs' fifth shutout of the season.
Pena yielded one hit over five innings out of the bullpen in the Rookie-level Arizona League on Aug. 4, 2009, but that's as close as he'd gotten to a one-hitter during his six-year Minor League career.
Saturday's outing was the latest in a run of solid starts for the Texas League All-Star. After going 1-4 with a 4.46 ERA through his first seven outings for Arkansas, Pena is 4-0 with a 1.68 mark in his last eight starts. Overall, he's 5-4 and tied for third in the league with a 2.94 ERA.
Pena believes the reason behind the bipolarity in the numbers is a simple. Like the slider he threw to Van Stratten, he was leaving too many pitches up in the zone.
"I've been making some adjustments in my side sessions," he said. "My pitching coach [Trevor Wilson] talked to me about working down more and focusing on just throwing strikes, and that's something that has carried over to games. When you miss down, the mistakes don't hurt as much, so that's what I've been focusing on."
Thanks to the improved results since early May, Pena's beliefs in his ability to pitch at the Major League level haven't changed much since his statement in the spring. Well, maybe they've changed a little.
"It's given me more confidence that I can pitch up there," he said.
Angels top prospect Jean Segura hit his eighth homer and drove in two runs for the Travelers, who got three hits from Casey Haerther.