The feat occurred less than two weeks after Carlton Smith, Austin Creps and Luis Perdomo combined on a 2-0 victory over Delmarva and the first no-hitter in Lake County history.
"It's pretty special," said Lake County first-year manager Chris Tremie, who played 14 years in the Minor Leagues and saw three no-hitters in-person. "I haven't witnessed it before. I've never heard of two no-hitters in nine days."
In this one, Rondon (6-4) walked two and struck out five over six frames. He set down the first five batters before walking Brandon Tripp in the second. His only other blemish was a walk to Daniel Figueroa in the sixth.
"Hector was very aggressive with his fastball," said Tremie, who lifted the 19-year-old after 83 pitches. "He got himself in good counts and was more consistent with making his pitches. He did a great job."
Rondon is 3-2 with a 1.73 ERA in five starts this season against the Shorebirds (4-8), who have been blanked six times, three by the Captains. Rondon, who was signed with Cleveland as a non-drafted free agent in 2004, went 3-4 with a 5.13 ERA in 11 starts in the Gulf Coast League last season.
Wagner fanned five without issuing a walk in three innings. He hit Christopher Vinyard with a pitch with two outs in the seventh but set down the next seven batters for his 10th save. The 23-year-old right-hander got Brandon Snyder to fly out to right field for the final out.
Lake County (9-3) did all of its scoring in the second as Niuman Romero ripped a two-run double and scored on an error by second baseman Miguel Abreu.
Delmarva starter Kyle Schmidt (3-5) took the loss after giving up three runs -- two earned -- on six hits with two walks and six strikeouts in six frames.
Ryan McConnell is a contributor to MLB.com. This story was not subject to the approval of the National Association of Professional Baseball Leagues or its clubs.