Girvin Imrie, an engineer from Cupar, Fife, grabbed his 20-year-old victim from behind and raped her.
The attack took place in a garden at the rear of Howe of Fife Rugby Club, Cupar, on May 5, 2013.
After the jury at the High Court in Glasgow returned its verdict, Imrie, 25, sat in the dock crying. He will be sentenced next month.
The woman, who cannot be named for legal reasons, said in evidence that she was at the rugby sevens event at Duthes Park, Cupar, with friends and ended up at the clubhouse. She told advocate depute Shanti Maguire, prosecuting, that after a few drinks she decided to go to the toilet but ended up outside. The woman said: "I was very happily drunk. I remember thinking I had to phone my boyfriend, but I can't remember if [I did]."
Ms Maguire said: "What happened next?" and she replied: "I just remember somebody being behind me. I know he was quite strong. He was hurting my arm. I was scared. I remember a big dark shadow. He never said a word." She said the only part of him she could see was his hands as he held her in a vice-like grip and raped her.
The court heard that the hat Imrie was wearing that night had been found close to where the rape took place.
After hearing an incident at the rugby club was being investigated by police, Imrie claimed he had had consensual sex in the garden area that night with the woman.
Imrie told his defence solictor advocate Iain Paterson: "It was a joyful occasion, We were having fun with each other. She was drunk and in good spirits."
Judge Lord Kinclaven remanded Imrie in custody and ordered a background report. He will sentence him at the High Court in Edinburgh on October 1.