MLB: Chicago Cubs 1, Pittsburgh 0

PITTSBURGH, Aug. 3 (UPI) -- Matt Garza teamed with two relievers on a four-hitter Wednesday and Starlin Castro hit a homer in the eighth to give the Chicago Cubs a 1-0 win over Pittsburgh.

Garza (5-8) went seven-plus innings and allowed all the Pittsburgh hits with two walks and seven strikeouts.

Sean Marshall came in for Garza in the eighth to retire three straight batters after Garza had issued a leadoff walk.

Carlos Marmol worked the ninth, hitting Derrek Lee with a pitch to start the inning. Lee reached second on a sacrifice, but Marmol then struck out both Pedro Alvarez and pinch-hitter Ryan Doumit to claim his 22nd save.

Castro's homer came on a 3-2 pitch off reliever Chris Resop (3-3). Starter Charlie Morton had given up five hits and struck out seven in seven scoreless innings.

Pittsburgh lost its sixth straight and has dropped eight out of nine. After climbing into first place in the National League Central last month, the Pirates have fallen 6 1/2 games behind Milwaukee and are below .500 for the first time since June 21.