A Melbourne church youth leader claimed his rape of an unconscious 14-year-old girl, who he later tried to kill, was prompted by his "sexual demons".

The Supreme Court was today told that Michael Tuano Hermogenes, 25, suffocated the girl at her home in Caroline Springs in May last year with her stockings after plying her with alcohol.

Crown prosecutor Andrew Grant said that after Hermogenes made the girl unconscious, he raped her and took her body to the bathroom.

He piled her clothes nearby and went to buy petrol, which he then poured over the girl and around the house.

Hermogenes set the girl and the house on fire after taking photos of her while she was naked and unconscious.