Chris Duncan shook off an August slump with a three-run homer and an RBI single and the Cardinals ruined Cecil Cooper's managerial debut with a 7-0 win over the Astros on Tuesday night. Phil Garner was fired on Monday and replaced by Cooper after Houston limped to a 58-73 record. But the Astros looked just as bad with Cooper in charge, plagued by mediocre pitching and feeble hitting. "This wasn't what I planned," Cooper said. "We were all excited. This kind of takes the steam out of it."