In only four innings, Cingrani threw 79 pitches before he was lifted. He allowed three runs and six hits with two walks and two strikeouts. In his fourth and final inning, Cingrani's normally low-to-mid 90s mph fastball was topping out at 89 mph.
"It did drop a little," said Cubs first baseman Anthony Rizzo, who hit a booming two-run homer to center field in the first inning. "He's got a good fastball that has good run to it. With him, it's just about getting a pitch over the plate and hitting. Fortunately enough we got to him early."
On the plus side, Cingrani denied that there was anything wrong, health-wise.
"I was just a little fatigued," Cingrani said. "I was just laboring. That was it."
Rizzo's homer was one of three straight long drives to center field. The first inning has been difficult for Cingrani, who has given up seven runs over the first inning in six starts this season and six runs combined over his other 26 1/3 innings pitched.
"Other than the St. Louis game [April 2], when he was really on top of his game and really electric, I think he's been finding his way," Reds manager Bryan Price said. "Especially early in the games of the other starts. We just want to make sure that he's strong and really able to command his fastball. When push comes to shove, we've talked a lot about his fastball, but when he's got his velocity and his command, there's not as much need for the off-speed stuff."
The Reds evened the game in the bottom half against Cubs starter Edwin Jackson, with Todd Frazier hitting a two-run double off of the left-field wall to score Joey Votto and Jay Bruce.
Brayan Pena led off the second inning with his first homer for the Reds, hitting Jackson's 2-0 pitch into the visitor's bullpen in right field. Jackson then retired 10 of his next 11 batters and the Reds would soon play from behind the rest of the night.
"You're always thinking you're in the game," Frazier said. "We just couldn't figure it out with the bats. We had a couple of good innings, but not that dominating inning that we're looking for."
Chicago made it a 3-3 game in the third as Cingrani labored again, allowing a one-out single and a walk before Starlin Castro hit an RBI single to center field. Mike Olt grounded into a double play to minimize the damage.
Cingrani did not allow any runs in the fourth inning, even with a slowing fastball, but Price turned to reliever Nick Christiani for the fifth. It's the second time this season that Cingrani has only pitched four innings. He hasn't completed seven innings since his 2014 debut vs. the Cardinals.
"He wasn't real sharp and his velocity started to back down a little bit that last inning," Price said. "He wanted to go back out and pitch. I felt it was the right decision to get him out of there. It just didn't seem like it was working for him tonight. It didn't seem like we should keep running him out there expecting a different result."
Cingrani, who is 2-2 with a 3.34 ERA this season, wasn't worried about feeling fatigued.
"It's just part of the season. I'll make some minor adjustments and see where it goes," he said.
Christiani faltered in the two-run fifth inning that put Chicago ahead. Following Junior Lake's leadoff double, Christiani walked Rizzo and Castro with eight straight balls. Olt's fielder's choice to shortstop plated the go-ahead run. Nate Schierholtz hit a sacrifice fly to left field with Rizzo's slide avoiding Pena's tag at the plate.
In the Reds' fifth, Billy Hamilton stole third base standing up with one out. There were two outs when Brandon Phillips lined an RBI single to left field against Jackson to make it 5-4.
The Cubs blew it open in the ninth as nine men batted and scored four runs. Sean Marshall didn't have it as he faced eight batters and gave up four hits and a walk, including a two-run single by Schierholtz and an RBI double by Emilio Bonifacio.
Cincinnati has lost four of its last five games as it finished April with a 12-15 record.