Shin-Soo Choo homered on Joe Blanton's first pitch of the game Thursday, the first of Cincinnati's three homers off the right-hander, and the Reds pulled away to a 5-4 victory over the Los Angeles Angels.
The Reds took two of three during the first interleague series to open a season.
Todd Frazier had a solo homer off Blanton (0-1), and Chris Heisey's two-run shot put Cincinnati up 5-3 in the fifth. Blanton gave up five runs and seven hits in five innings.
Bronson Arroyo (1-0) gave up three runs in six innings, including Josh Hamilton's two-run single that was his first hit for the Angels. Albert Pujols drove in a pair of runs with a sacrifice fly and a groundout.
Aroldis Chapman pitched the ninth for his first save.