Arrieta cut that deficit in half with a homer of his own to left-center in the third in what was his first at-bat of the spring.
Arrieta came up again in the sixth with the bases loaded and admitted he was thinking grand slam.
"When you hit a homer in your first at-bat, you're like, 'It'd be cool to do it again, especially with the bases loaded,'" Arrieta said. "I got a little overzealous with a changeup and tried to leg it out. It was a decent day at the plate."
The Cubs tied things up at 2 in the fifth when Kris Bryant doubled home Munenori Kawasaki.