Anything that proves that documents were altered, fabricated or inaccurate also "should be immediately turned over to the appropriate law enforcement agencies," attorneys Leslie Stovall and Larissa Drohobyczer said in a statement emailed to media in the U.S. and abroad.
"Disputes regarding the accuracy of documents are generally questions of fact to be decided by the jury," they said.
Ronaldo's attorney, Peter S. Christiansen, declined to respond.
On Wednesday, Christiansen issued a statement denying wrongdoing by Ronaldo, branding documents that led to media reports about the rape claim "complete fabrications" and asserting that the encounter in a Las Vegas hotel penthouse bedroom was consensual.
The documents became public because they were stolen by a hacker in Europe and put up for sale, Christiansen said.
Stovall and Drohobyczer said Christiansen acknowledged that documents upon which the allegations are based "were obtained from Cristiano Ronaldo or individuals acting on his behalf."
Drohobyczer declined, via text message, to provide additional comment.
The statement was issued in Las Vegas several hours after the German weekly magazine that first published the rape allegation against Ronaldo said in Berlin that it stands by its story.
"We have no reason to believe that those documents are not authentic," Der Spiegel spokesman Michael Grabowski said. "We have meticulously fact-checked our information and had it legally reviewed."
Stovall and Drohobyczer represent Kathryn Mayorga, 34, a former model who filed a civil lawsuit two weeks ago in Nevada state court seeking money from Ronaldo and a court order to void a non-disclosure agreement the court filing acknowledges she signed when she accepted $375,000 in 2010 to keep quiet.
Las Vegas police also reopened a criminal sexual assault investigation at Stovall's request.
The Associated Press typically does not name people who say they are victims of sex crimes, but Mayorga gave consent through Drohobyczer to make her name public.
In a separate email, Mayorga's attorneys on Thursday listed 18 U.S. and European agencies ranging from Interpol to Scotland Yard, the FBI and U.S. state attorneys general that they said they asked to investigate whether Ronaldo and anyone associated with him violated laws based on information contained in the documents.
It was not immediately clear if investigators in Portugal, Spain, England, Italy, Ireland and the U.S. states of Nevada and California were acting on that request.
Ronaldo, 33, is from Portugal and plays for the Italian club Juventus and his national team. He began his career at Sporting Lisbon before moving to Manchester United and then Real Madrid in the summer of 2009 for a then-record sum of 94 million euros, or about $130 million.
Some of his corporate sponsors, including Nike and video game maker EA Sports, have expressed concern about the rape allegation.
Portuguese Prime Minister Antonio Costa has spoken in Ronaldo's defense, while citing his successful international career.