The Reds let a four-run lead get away in the late innings, but quickly jumped on reliever Scott Downs to produce the winning run in the ninth.
Downs hit Choo with his first pitch of the inning and Chris Heisey then put down a sacrifice that moved Choo to second.
Votto followed with his single to right that bounced off the glove of first baseman Albert Pujols and delivered Choo.
Brandon Phillips hit a three-run homer for the Reds to highlight a four-run fourth inning. A solo shot by Howard Kendrick in the fifth and a two-run blast from Alberto Callaspo in the seventh triggered the Los Angeles comeback.
Aroldis Chapman picked up the win by working the top of the ninth, escaping unscathed after walking a batter.
The teams have split the first two games of their season-opening series.