CHICAGO (AP) – Pedro Alvarez had two hits and two RBIs and the Pittsburgh Pirates overcame two home runs by Starlin Castro to beat the Chicago Cubs 7-6 on Tuesday night. Russell Martin drove in the go-ahead run on a sacrifice fly in the eighth inning for Pittsburgh and Jason Grilli closed with a perfect ninth. Cubs right-hander Pedro Strop (0-1) walked two batters in the eighth and recorded only one out before being replaced by left-hander James Russell. Russell immediately walked Pedro Alvarez to load the bases and Martin followed with a fly ball to right field that made it 7-6. The Cubs tied the game in the seventh against Tony Watson (1-0) on Anthony Rizzo’s hit up the middle scoring Emilio Bonifacio, who went 3 for 5 and is batting .515.