Pittsburgh’s Pedro Alvarez hit a first inning grand slam home run off Cardinals starter Lance Lynn to help power the Pirates to 7-3 win over the Cardinals on Saturday. Lynn (10-4) struggled in his 3rd straight start, after allowing 6 earned runs in 5 innings of work. Meanwhile, Pirates starter Jeff Karstens allowed just 2 earned runs over 7 innings. Cards left fielder Matt Holliday had 2 hits, along with an RBI.The Cardinals have fallen 3 and half games behind the Cincinnati Reds in the National League Central. The Pirates go for their first sweep at Busch Stadium today, for the first time since 1991.