The woman told police she was on her way out of the toilet at Söderstadion during a match between Hammarby and visiting Halmstad when a man confronted her and forced her back into the toilet.
"He dragged her in and she fell and hit her face on the toilet stall door. Her forehead was inflamed and tender and she chipped one of her front teeth," Söderort police spokesperson Linda Feldt told the Aftonbladet newspaper.
The man then proceeded to rape the woman until she was able to call out for a friend, according to the paper.
There were nearly 12,000 spectators in attendance at the time of the attack, which took place around 6pm during the second half of the football match.
Police realized it was impractical to prevent the entire crowd from leaving the stadium while they searched for the perpetrator, of whom they have a "very weak, general description".
Police described the suspected rapist as being a man between 25- and 30-years-old and approximately 185 centimetres tall.
"He had long, dark, wispy hair, brown eyes, black pants and a white t-shirt with a print," Feldt told Aftonbladet.
Police have launched a preliminary investigation the rape of the woman, who was taken to the hospital following the incident.