The game was nearly a repeat of an April 14 outing at Wrigley Field against Cincinnati when Arrieta retired the first nine batters he faced. On Sunday, he retired the first 11 before Todd Frazier lined a home run to left with two outs in the fourth.
"It was a good breaking ball and it was down," Arrieta said of the pitch to Frazier. "He used his ability to go down and get it and was able to put enough wood on it to get it out."
Last season, Arrieta carried a no-hitter into the seventh inning three times -- including June 24 against the Reds when he had a perfect game through six innings.
On Sunday, he had back-to-back tough innings in the fourth and fifth, and his pitch count was at 92 through five. But he returned for the sixth and struck out two of the three batters he faced. What happened?
"In the fifth, I sped up a little bit, got out of my rhythm, a little uncharacteristic there," Arrieta said. "As things got a little more tense there, my emphasis was on not making a mistake, damage control and making pitches to avoid a big inning."
Manager Joe Maddon watched Arrieta adjust as the game progressed.
"After the home run, it seemed he was off command-wise, but still his stuff was good," Maddon said. "That's what you talk about when a guy doesn't cave in. That matters. You're not going to have your best stuff, best everything every night. You've got to be able to win with less than your best, and he did. That's a tribute to him and his work and his mental focus."
This most likely won't be the last time Arrieta faces the Reds. He's ready.
"It's something I can use to my advantage," Arrieta said. "Obviously, you want to stay out of patterns over and over. They're smart and watch the same video I do. They try and sequence things out. They know I like to throw cutters in full counts. Those are things moving forward that I'll use to my advantage."
Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter @CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.