Pirates 7, Cubs 6: Pedro Alvarez had two hits and two RBIs and Travis Ishikawa knocked in a pair of runs as visiting Pittsburgh claimed the opener of a three-game series with Chicago.

Andrew McCutchen, Russell Martin and Neil Walker each added two hits and an RBI for the Pirates, who have won three of four against the Cubs this season. Tony Watson (2-0) had his streak of 24 consecutive scoreless innings dating to Aug. 3 halted but was credited with the win and Jason Grilli worked a perfect ninth for his second save.

Starlin Castro recorded the first two-homer game of his career and had three hits and four RBIs while Emilio Bonifacio went 3-for-5 with an RBI for the Cubs. Pedro Strop (0-1) recorded only one out in the eighth and was charged with the go-ahead run to take the loss.

The Pirates jumped on starter Edwin Jackson for four runs in the first as Alvarez doubled home two and scored on Walker's single before Ishikawa added a sacrifice fly. Chicago cut into the lead on Bonifacio's RBI single in the second and tied it on Castro's first blast, a three-run shot into the left-field bleachers in the third.

McCutchen's RBI single and Ishikawa's run-scoring triple put the Pirates back on top, but Castro went deep again in the sixth and Anthony Rizzo singled home the tying run in the seventh. Martin's sacrifice fly in the eighth gave Pittsburgh its third lead of the night and Mark Melancon and Grilli each worked 1-2-3 frames to close it out.

GAME NOTEBOOK: Bonifacio is 14-for-21 against the Pirates this season. … Jackson was charged with six runs on nine hits in 4 2/3 innings while Pittsburgh starter Charlie Morton gave up five runs on eight hits over six frames. … Cubs manager Rick Renteria was ejected by home plate umpire Jeff Nelson for arguing balls and strikes in the ninth inning.