The Braves' No. 3 prospect struck out nine over six innings on Saturday, pitching Gwinnett to a 4-0 victory over the Charlotte Knights.
Delgado, who went 5-5 with a 3.84 ERA in 21 starts for Double-A Mississippi, allowed three hits and three walks.
"I never thought, 'I have to do a really, really good job,'" he told the Gwinnett Daily Post. "I threw very well and I just tried to stay [focused]."
Signed as a non-drafted free agent in 2006, Delgado allowed just one baserunner over the first three frames -- Lastings Milledge singled in the second -- before running into a jam in the fourth. Back-to-back walks to Dallas McPherson and Milledge loaded the bases with two outs, but he retired Josh Phegley on a fly ball to center field.
The 21-year-old right-hander also dealt with some trouble in the sixth, when the Knights had two on and two out, but he struck out Milledge.
"I thought he threw the ball extremely well tonight," Gwinnett pitching coach Marty Reed said. "He located his fastball well early in the game and his changeup was outstanding tonight. He had them off-balance for the entire outing. I thought he pitched with a lot of confidence tonight."
Delgado said his outing in the big leagues, in which he allowed three runs over four innings against Texas, kept him from getting too worked up on Saturday.
"If I hadn't pitched there, maybe I would have come here and been a little bit nervous, but I didn't even think about it," Delgado told the newspaper.
Reed, who worked with Delgado last year at Mississippi, said he can't expect the Panama native to pitch this well every night.
"I'd love to say I'd expect exactly what happened tonight, but maybe that would be wishful," Reed said. "I'm just looking for him to show some consistency. He doesn't have to pitch as well as he did tonight. Can he throw his fastball for strikes, can he hit with the breaking ball, can he hit with it behind in the count? Those are things we're looking for."
Reed called it a matter of when, not if, Delgado becomes an "outstanding Major League pitcher." With the young arms in the system -- Delgado, Julio Teheran, Arodys Vizcaino and Mike Minor -- the Braves should be set for years to come, he said.
"You've had them when they weren't very good, then they're building and learning," Reed said. "Now you're just seeing it come to a head, where guys who are exceptionally talented buy into what we're doing. Now you see them throw well. It continues to build value in our organization.
"That's why everybody's trying to get our young pitching. And I'm glad we didn't trade it because it's really hard to come by -- especially those guys right there. ... Keeping those four guys, that puts you in a good situation these next three or four years, I would think."
Cory Gearrin, who's made 18 appearances for the big club this season, gave up a hit in the seventh before Jairo Asencio struck out three over the final two innings to complete the G-Braves' ninth shutout.