The Cubs wasted little time attacking Urena. Dexter Fowler ripped the rookie's first pitch of the night into center field for a single. Kris Bryant drew a walk, and Anthony Rizzo took a big cut at a first pitch. With the count 1-2, Rizzo delivered an RBI double.
Jorge Soler's RBI grounder to second gave Chicago two runs before the Marlins came to bat.
"They attacked my fastball early," Urena said. "That's what cost me those two runs in the first inning. That's part of the game.
"I was able to make an adjustment. I was able to [adjust] my curveball, changeup, and that helped me out to go later into this game."
Urena, making his second big league start and first at home, was able to throw his breaking ball and changeup for strikes. It helped him end the outing on a positive note as he gave up three runs in six innings, striking out four.
"I thought that was a big step forward for him," manager Dan Jennings said. "He's a gutsy kid. He competes. He challenges the hitters. He's going to have a nice future, nice career."
Urena is Miami's No. 2 prospect, according to MLB.com. He was 4-0 with a 1.21 ERA in six Triple-A starts. He was called up to round out the rotation because three starters are on the disabled list.
"The quality of his strikes, I thought they greatly improved," Jennings said. "He threw some tremendous changeups in key situations, key counts. It benefited him to be able to use that pitch."
Joe Frisaro is a reporter for MLB.com. He writes a blog, called The Fish Pond. Follow him on Twitter @JoeFrisaro and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.