Updated

CINCINNATI (Reuters) - Rookie Starlin Castro marked his first appearance for the Chicago Cubs by hitting a debut record six RBIs and smashing a three-run homer in his first at-bat on Friday.

The 20-year-old shortstop from the Dominican Republic was called up from Double-A Tennessee earlier on Friday and helped his new team mates to a 14-7 victory over the Cincinnati Reds.

"I don't believe it," Castro told reporters after hitting Reds starter Homer Bailey over the right field wall.

In the fourth, Castro hit a three-run triple off Reds reliever Micah Owings to beat the previous mark of five for RBIs on a debut, recorded most recently by Ben Grieve for the Oakland Athletics in 1997, according to Elias Sports Bureau.

(Writing by Patrick Johnston in Singapore; Editing by Clare Fallon)