A 22-year-old man charged with rape said relations between him and the alleged victim were consensual.
David Day, of Lower Hampton Road, Sunbury, denies rape after it is alleged he forced himself upon a woman he met on a night out.
He gave evidence at Kingston Crown Court on February 27.
The court heard it claimed Mr Day locked the woman, in her 20s, in a bedroom in his friend’s house in Kew where the alleged attack happened.
He said: “I didn’t get any indication that she was uncomfortable with what happened.”
The school lab technician had been out drinking with a friend when he met the alleged victim, who was out with university friends, the court heard.
After visiting a number of bars the pair got a taxi back to Kew with Mr Day’s male friend and the alleged victim’s flatmate.
Mr Day, a Nottingham University graduate, told the court he had drunk four alcoholic drinks and four to six shots during the evening.
Mr Day claimed he had consensual sex with the alleged victim, after which she became upset because she told him she had a boyfriend.
Mr Day, who is represented by Steven Hadley, told the court her revelation about a boyfriend had surprised him.
He said: “It would have been nice to have known beforehand. I don’t know if it would have changed anything, but it would have been nice to know.
“It (the relationship) seemed very dysfunctional by what she was saying.
“It didn’t seem like a relationship she was enjoying.
“She said she felt like a bad person having had sex with me.
“I was trying to reassure her that if the relationship she had was the way she said it was then maybe she wasn’t such a bad person for it.”
He fell asleep and the alleged victim left the house at about 6am, the court heard.
The trial continues.