Cubs 4, Pirates 1: Cody Ransom blasted a tiebreaking three-run homer in the seventh and Edwin Jackson tossed seven strong innings as host Chicago salvaged the final contest of the three-game series.

The Cubs' late-inning heroics spoiled the day for Pittsburgh starter Jeff Locke, who didn't allow a hit until Dioner Navarro's two-out single chased him in the sixth. He was in and out of trouble all day thanks to seven walks, and a pair of free passes in the sixth set up Scott Hairston's game-tying sacrifice fly.

Jackson (2-8) turned in his best outing with the Cubs, allowing one run on four hits over seven innings and striking out eight. Kevin Gregg worked around a pair of hits in the ninth for his seventh save.

Garrett Jones' RBI single in the fourth put the Pirates on top, and they stayed there until the Cubs rallied without a hit in the sixth.

Chicago took control in the seventh, when Ryan Sweeney and Darwin Barney singled ahead of Ransom's blast to left off left-hander Justin Wilson (5-1).

GAME NOTEBOOK: The Cubs did not record a hit before the fifth inning in the three-game series. … Cubs SS Starlin Castro went 0-for-4 and is 2-for-33 over his last nine games. … Jackson improved to 2-7 all-time at Wrigley Field with his first home win this season.