Kathryn Mayorga says she was attacked by the Portuguese footballer in a hotel room in the U.S. city that year.
Mayorga told Der Spiegel she no longer felt bound by the non-disclosure agreement as she suffers from the consequences of the night in 2009.
With Juventus superstar Cristiano Ronaldo yet to take Serie A by storm since his arrival from Real Madrid, a former Brazil worldwide believes the five-time Ballon d'Or victor "will suffer" in Italy at times. At the time of the alleged sexual assault, on June 13, 2009, he had just moved from English Premier League club Manchester United to Real Madrid for a 94 million euro transfer fee, a world record at the time.
The Italian club declined to comment on the Der Spiegel report on Friday.
"No, no, no, no, no". What they said today [was] fake news. In every game you want to score goals and we had some chances to do so. It's normal. They want to be famous. Yeah, but it is part of the job.
Ms Mayorga, 34, is reported to have filed a rape report with Las Vegas police after the alleged incident. Nevada recently changed its law regarding the statute of limitations in sexual assault cases, according to Sports Illustrated legal expert Michael McCann, lengthening it from four to 20 years.
An attorney for Ronaldo, Christian Schertz in Berlin, did not immediately respond to emails from AP. After contacting police the next day, she went to a hospital and underwent a medical examination.
The civil lawsuit filed in state court in Las Vegas alleges Ronaldo raped Mayorga, who was then 24, in his penthouse suite at a Las Vegas hotel and hired a team of what the document called "fixers" to shape the monetary settlement, obstruct a police criminal investigation and trick Mayorga into taking $375,000 to keep quiet.
The complaint further stated that after she refused his demand to perform oral sex and said she wanted to leave, Ronaldo pulled her into a bedroom and anally raped her while she repeatedly screamed "no".