Stephen Coxen admitted he had been “rude” towards the woman on the night in question and their time together became upsetting, but he denied the allegation he faces.
The 23-year-old told the court he was “really shocked” in 2014 when he initially found out the claim was being made against him.
Coxen, from Bury in Lancashire, is being sued by the woman who accuses him of raping her in St Andrews after a night out in September 2013.
He denied the charges and in November 2015 a jury found the case against him not proven – a verdict of acquittal.
The alleged victim, who cannot be named for legal reasons, has brought a civil action to the Personal Injury Court in Edinburgh. Coxen was giving evidence in his defence yesterday.
He told the court he was visiting his friend Dominic Hurst in St Andrews on the weekend in question and they went out with some friends to the Lizard Lounge venue after having drinks together.
He said he was in the smoking area of the club when the alleged victim tapped him on the shoulder and started kissing him.
“I was quite surprised, but I just went along with it,” he said, adding he was happy and they were “snogging” passionately.
Coxen told how they later ended up at the woman’s flat after he was thrown out of the club following an altercation with a group of boys.
“She seemed to be enjoying my company,” he told the court, adding they got undressed in her bedroom and “started having intercourse”.
He said at some point she pulled away and when he asked if she was OK, she nodded.
Shortly after that, he looked down and saw blood, he told the court.
“Then I quickly got off the bed and ceased intercourse and I said something to the effect of ‘that’s disgusting, I thought you were all right’.”
“I got dressed and I left the property quite quickly.”
Mr O’Rourke asked Coxen how he now feels about the way he reacted at the time, when he was aged 18.
“Immature, stupid,” Coxen replied.