Portugal superstar Ronaldo is accused of raping Mayorga in a penthouse at the Palms Casino Resort in June 2009 after a night spent partying, and of later paying her $375,000 in hush money.
The forward, 34, has vehemently rejected the claims, and says that any encounter with Mayorga was consensual.
He was backed by his mother Dolores Aveiro earlier this week at a PR event in Lisbon.
“I have confidence in my son when it comes to what happened,” she said, according to Marca.
“When she went there, it wasn’t to play cards. It was to do something. I know the son I have.”
It is the latest backing from Dolores, who is known to be extremely close to her son.
After the news initially emerged last year of Mayorga’s claims against Ronaldo, his mother posted a cartoon-style picture of the former Real Madrid star with a Superman cape, along with hashtags including “#Justice for CR7.”
Dolores revealed in a separate interview this week that she has recently had an operation on her breast amid a cancer scare.
“I was operated on another breast in Madrid, I’ve had radiotherapy and now I’m fighting for my life,” she is reported as saying.
It follows surgery in 2007, when she had a lump removed from her right breast.
Ronaldo has not commented on the health scare reports, but is also known to be consoling girlfriend Georgina Rodriguez, 25, after her father recently died in Argentina at the age of 70.
Ronaldo himself lost his father, Jose Dinis Aveiro, when he died of liver failure when the striker was just 20 years old and establishing a name for himself at Manchester United.
The case into the rape allegations against Ronaldo was formally reopened by Las Vegas police last year. Mayorga is said to have been moved by the #MeToo campaign, and is seeking justice after continuing to suffer trauma over the alleged ordeal.
Ronaldo has repeatedly and vehemently denied the claims, and said at the end of last year that he was “completely calm and very confident that soon everything will be clear.”