Rape-accused Joseph McCann was branded “pure evil” as a teenager described how she and her little brother were abused at knifepoint.
Mr McCann 34, from Harrow, allegedly tricked his way into a family home in Greater Manchester on 5 May.
He tied up a mother with hair straighteners and molested her children, aged 17 and 11.
The girl said she feared becoming Mr McCann’s “sex slave” before jumping out of a first-floor window to escape.
Mr McCann denies 37 offences against 11 victims.
In a video-taped police interview played in court, the 17-year-old girl described how her attacker had initially grabbed her, put his hand over her mouth and told her to “shut up”.
She said: “I managed to wriggle out of it. He pulled me down onto the floor. That’s when he must have knocked me out. His knife must have cut me in a few places.
“My mum was like, ‘what are you doing?’, trying to stop him.”
The teenager claims he took cocaine and swigged vodka before repeatedly sexually assaulting her and her brother.
She said: “When I did not do what he said he kept putting the knife up to me.
“In my head I was trying to think of alternative ways of trying to get out of this situation.”
‘You are mine’
She went on: “I mentioned my brother was 11 and he said, ‘I didn’t know that, how old are you?’ I said 17.
“He said to me, ‘you are going to Europe tomorrow, you are mine’.
“At this point my life flashed before my eyes. I thought of marriage and everything. I’m going to be his sex slave. I thought, I’m not having this.”
The court previously heard how the girl fractured her heel when she jumped out of a window naked to escape.
The trial continues.