Cubs 7, Pirates 4: Starlin Castro homered and drove in four as host Chicago handed Pittsburgh its season-high seventh straight loss.

Chris Rusin (1-2) struck out six and allowed two runs in five innings to earn his first major-league win and Anthony Rizzo double in a pair for the Cubs, who have won six of seven - including four straight against the Pirates. Carlos Marmol recorded the final three outs for his 20th save.

Andrew McCutchen hit his 27th homer for Pittsburgh, which fell three games behind St. Louis for the second wild card spot in the National League. The Cardinals dropped an 8-5 decision to the Los Angeles Dodgers on Friday.

Chicago got to James McDonald (12-8) on Castro’s RBI single in the third and broke the game open with three runs in the fourth. McDonald loaded the bases on three walks before being replaced by left-hander Justin Wilson, who surrendered Rizzo’s two-run double to right.

The Pirates battled back to cut it to 4-3 but Castro came up with two on and two outs in sixth and ripped a first-pitch fastball from Jared Hughes into the stands in left for his 13th homer.

GAME NOTEBOOK: Pirates 2B Neil Walker did not start for the 16th straight game due to back tightness. He struck out in a pinch-hitting appearance. … Cubs LF Alfonso Soriano drove in his 97th run with a single in the fourth. He needs one homer and three RBIs for his first 30/100 season since 2005. … Pittsburgh 3B Pedro Alvarez (wrist) returned to the lineup after missing a game and went 1-for-4 with two RBIs.