Mayorga alleges in the lawsuit that she was pressured into signing a non-disclosure agreement to keep the alleged rape secret and is seeking no less than US$200,000 in penalties and damages.
The complaint was first reported by the German magazine Der Spiegel. Lawyers for Ronaldo have reportedly threatened to sue the magazine over the story.
In the suit, Mayorga said she met Ronaldo, who was then 24 years old and about to secure a transfer from Manchester United to Real Madrid, on the evening of June 12, 2009 at the Rain Nightclub in the Palms Hotel and Casino in Las Vegas.
The footballer is said to have entered the room with his penis hanging out of hit shorts. 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 without a condom while she screamed "no, no, no" and covered her vagina, the complaint said.
"When Cristiano Ronaldo completed the sexual assault of the plaintiff, he allowed her to leave the bedroom stating he was sorry, he was usually a gentleman," it said.
Under pressure from Ronaldo's "fixers," Mayorga settled the case "in exchange for a payment of US$375,000 and non-disclosure of the sexual assault," the lawsuit said.
It claimed the agreement should be voided because she was "incompetent and lacked the mental capacity to participate in negotiations and settlement of her claims due to the injuries suffered during the initial sexual assault."
The suit also called for the agreement to be dismissed because it amounted to concealment of a crime for which there is no statute of limitations.
The unidentified "fixers" were named as co-defendants in the lawsuit, which also accuses the Juventus forward of violating the 2010 non-disclosure agreement.
In an interview with Der Spiegel, Mayorga, who has a degree in journalism from the University of Nevada, Las Vegas, said she was inspired to come forward in part by the #MeToo movement which has exposed the sexual abuse of women by powerful men.
Ronaldo is a five-time winner of FIFA's men's player of the year award.