James Loney and Manny Ramirez each added solo homers for the NL West-leading Dodgers, who have won three of their last five games. Russell Martin added two RBI for LA, which remained 3 1/2 games ahead of Colorado in the West.
Vicente Padilla (2-0) allowed two runs on six hits in six innings for the win. Jonathan Broxton earned his 33rd save of the season after working 1 1/3 scoreless innings.
Chris Young hit a two-run homer for Arizona, which has lost five in a row and six of its last seven games. It was Young's fourth homer in his last two games.
Max Scherzer (9-9) took the loss after giving up four runs on six hits in seven innings.
Ramirez was ejected in the third inning for arguing balls and strikes.