Brandon Phillips hit a three-run homer and Edwin Encarnacion added a solo shot for the Reds, who ended a season-high six-game losing streak.
Homer Bailey (2-2) got his first win in a month after he allowed three runs on six hits with a walk over 7 1/3 innings.
Willy Taveras had two outfield assists for Cincinnati, which included throwing out Kyle Blanks at home for the third out of the second inning.
Adrian Gonzalez, Everth Cabrera and Kevin Kouzmanoff each hit a solo home run for the Padres, who have lost eight of their last nine games.
Losing pitcher Josh Geer (1-7) gave up five runs on four hits over four innings.
Copyright 2009 by United Press International.