David Wells gave up four hits in six scoreless innings Saturday to get his first win for the Padres after being acquired in a trade with Boston on the last day of August.
Wells (1-2) walked one batter and struck out three.
Trevor Hoffman earned his 45th save.
Mike Cameron hit a two-run homer; Josh Bard hit a run-scoring infield single; while Dave Roberts scored a run and had two of the six hits for the Padres (87-74), who are tied with the Dodgers for the top spot in the NL West after a split of their last four games.
Los Angeles beat San Francisco, 4-2, and Philadelphia was eliminated from the NL post-season picture.
Scott Drew hit a solo home run for the Diamondbacks (76-85).
The loser was Edgar Gonzalez (3-4).