CARACAS (Reuters) - Venezuelan opposition leader Henrique Capriles held his governorship post in state elections on Sunday, leaving him well placed to challenge the government, should President Hugo Chavez's cancer necessitate a new presidential vote.

But the ruling Socialist Party's candidates had a strong showing elsewhere around the South American nation, taking 18 out of 21 governorship results announced by the election board, compared with the opposition's three.

(Reporting by Marianna Parraga; Editing by Sandra Maler)