"Keep throwing," Carreno said. "That's it. Keep pitching."
The right-handed Blue Jays prospect from San Cristobal, Dominican Republic, was 0-2 with seven starts in the Midwest League coming into Lansing's 5-0 one-hit shutout of visiting Kane County.
Carreno surrendered just one hit and a walk while striking out a season-high nine in his longest outing of the year.
"I feel very, very good because I had a good command of my fastball and my slider," he said.
The 22-year-old threw five perfect innings before issuing a walk to catcher Dusty Napoleon to start the sixth. Carlos Arrieche dropped in a ball in front of Lansing right fielder and Johermyn Chavez threw out Napoleon at second on a fielder's choice. Arrieche then was erased on an attempted steal by catcher Jonathan Talley.
Jeremy Barfield singled with one out in the eighth to end Carreno's no-hit bid.
Carreno started the season with the Auburn Doubledays of the New York-Penn League. He compiled a 2-0 record and an 0.82 ERA in two starts with Auburn before his promotion to Lansing in late June.
After struggling in the early going Carreno finally is starting to understand Class A hitters.
"Throwing first-pitch strikes [is important], because when you get behind the hitter they know what pitch you're going to throw next," he said.
Jason Roenicke wrapped up the one-hitter with 1 2/3 perfect frames.
Tyler Pastornicky was the main spark in the Lugnuts' batting order Sunday. The 19-year-old fell a homer short of the cycle, finishing up 3-for-3 with two RBIs.
Kira Jones is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.