He will be sentenced later.
The 20-year-old convicted rapist cannot be named to protect the victim’s anonymity.
He pushed the girl into the ladies toilets of the teen disco in December 2010 and raped her in a cubicle.
The pair were seen kissing shortly before the incident after his friends and her own girl friends had encouraged her to “meet”, or kiss.
The man pleaded not guilty at the Central Criminal Court to rape and sexual assault of the girl at a nightclub in a Co Donegal town on December 23, 2010.
The jury of seven men and five women returned the unanimous verdicts of guilty on both charges after deliberating for just over two hours.
The judge remanded the accused in custody after Sergeant Angela Cummins told the court that he had previously breached the conditions of his bail a number of times.
He will be sentenced in March when a victim impact report and an assessment of the accused by the Probation Services will be provided to the court.
Ms Justice Heneghan asked the lawyers to inform the court on that date of any case law pertaining to sexual offences committed by an accused of a young age. Gerard Clarke SC, for the Director of Public Prosecutions, said he didn’t think there would be much case law in that area but they would provide what existed.
The court heard how the accused kept putting his hand up her skirt and she kept pushing it away and told him to stop. She then told him she wanted to go find her friends in the smoking area.
He walked with her towards this area, holding her hand. She said she thought they were going to find her friends until he pushed her into the toilets.
She didn’t know what was happening and asked him to let her out as he took her into a cubicle.
“He had me up against the wall. He pulled down my underwear. I tried to pull them back up but he had me pinned,” she testified.
She said he pulled down his trousers and raped her. She had never had sex before, that it hurt and felt “excruciating” and she was screaming and crying.
A female friend of the victim met her afterwards and saw she was upset. She confronted the accused on the night and he told her he had done nothing. When she “kept at him” he told her, “yeah, she said yeah”.
The accused told gardaí that he had no recollection of being in the girls’ toilet in the nightclub.