Ike Davis also went deep among three hits and joined Russell Martin with two RBIs for the Pirates. Vance Worley (3-1) picked up the win, allowing four runs — one earned — on seven hits over six innings.

Adrian Gonzalez and Scott Van Slyke homered for the Dodgers, who had a three-game winning streak snapped. Los Angeles starter Josh Beckett lasted only 3 2/3 innings and was tagged for four runs and six hits in his return from the disabled list.

Walker and Davis hit solo shots in the second to rough up Beckett and stake the Pirates to an early lead. Gonzalez's sacrifice fly and Andre Ethier's RBI single in the third tied it, but Polanco went deep in the bottom of the inning and Walker added an RBI double later in the frame.

The Dodgers tied it at 4-4 on A.J. Ellis' two-run single in the sixth to get Beckett off the hook, but Pittsburgh answered with four runs in the sixth against Paul Maholm (1-5) and Jamey Wright. Gonzalez hit a two-run shot in the seventh and Van Slyke added a pinch-hit homer in the eighth to pull Los Angeles within one before Chris Perez melted down in a four-run eighth inning to break it open.

GAME NOTEBOOK: Polanco's home run was his first extra-base hit since he last went deep on July 2. … Pirates 3B Pedro Alvarez left before the start of the fifth inning with left knee discomfort. … Pirates LHP Justin Wilson and manager Clint Hurdle were ejected in the seventh after the former hit SS Justin Turner with a pitch in retaliation after Wright plunked CF Andrew McCutchen an inning earlier.