Starlin Castro hit one of Chicago 's three solo homers .
Felix Doubront pitched seven strong innings in his National League debut , sending the Chicago to a 5 - 1 victory in the doubleheader opener .
Starlin Castro hit one of Chicago 's three solo homers and Felix Doubront pitched seven strong innings in his National League debut , sending the Cubs to a 5 - 1 victory in the doubleheader opener .