The most popular soccer star in the world faces a struggle to keep his footing — and possibly his endorsements — amid a burgeoning scandal over newly resurfaced allegations that he sexually assaulted a Nevada woman in 2009.

Cristiano Ronaldo, 33, is the subject of a lawsuit filed in Las Vegas by Kathryn Mayorga, who publicly came forward to accuse the Portuguese superstar of raping her after she was separated from a group visiting his hotel penthouse at his invitation. While Germany's Der Spiegel first reported the alleged crime early last year, the accusations became a huge international story last week when the news magazine published excerpts from Mayorga's lawsuit.

In the suit, Mayorga claims she was coerced into accepting a payoff of $375,000 in 2010 to buy her silence and is seeking to overturn the non-disclosure agreement she signed at the time.

The Las Vegas police department announced this week that it was reopening its investigation into the events of June 13, 2009. Police responded to a call of sexual assault at the time, a spokesman for the department said, but the case was closed after "the victim did not provide detectives with the location of the incident or suspect description."

The Juventus striker has since denied the accusations, tweeting Thursday, “My clear conscience will thereby allow me to await with tranquility the results of any and all investigations.”

Soccer star Cristiano Ronaldo is pictured with Kathryn Mayorga, center, in Rain Nightclub in Las Vegas June 2009. Matrixpictures via AP

Ronaldo won't, at the very least, be able to evade a massive public relations hit as easily as he dodges opposing defenses on the pitch.

"Ronaldo is one of the most recognizable people on the planet," Sports Illustrated soccer columnist Grant Wahl told NBC News, "Along with Lionel Messi, he has been the best soccer player of the last decade, having played the biggest clubs in the world, Real Madrid and Manchester United.

"But I think Ronaldo’s status is in real danger here."

Forbes pegs the five-time Ballon d’Or winner as the third richest athlete in the world, having earned an estimated $108 million in salary and endorsements in the 12-month period ending in July 2018. As Tiger Woods could attest, however, those deals are not impervious to bad headlines.

Two of Ronaldo's biggest endorsers, video game manufacturer EA Sports and sportswear giant Nike, expressed concern Thursday over the nature of the allegations.

"We are deeply concerned by the disturbing allegations and will continue to closely monitor the situation," Nike, which has a reported $1 billion endorsement deal with Ronaldo, announced in a statement.

On the same day, the Portuguese national team dropped its best player from a pair of upcoming matches.

"Ronaldo and his people didn’t seem to show much concern at first," said Wall. "But if you look at the Der Spiegel report, these are very serious allegations.

"Clearly, Nike and EA Sports are taking this seriously."

In Italy, though, the coverage of the accusation surrounding the country's biggest sports figure have been buried in the major newspapers, said journalist Justin Salhani, who covers Italian sports and culture.

Those same publications have been splashing Ronaldo's image across the front pages ever since he signed with the country's most popular soccer team, Juventus, in July, hailing him as a savior ready to take the club to a long-coveted Champion's League title.

"When you take into account the state of Italian soccer, which for the last 10 or 15 years has been in such a poor state as England and Spain have overtaken it," said Salhani, "to have somebody of Ronaldo's scale come to Juventus, it’s a validation to Italian football — and of Italian football fans.

"He’s not just Juventus' crown jewel, he’s Italian soccer’s crown jewel."

While Nike and EA Sports have been publicly tactful, Juventus doubled down in support of its No. 7 on Thursday:

.@Cristiano Ronaldo has shown in recent months his great professionalism and dedication, which is appreciated by everyone at Juventus. 1/1 — JuventusFC (@juventusfcen) October 4, 2018

The events allegedly dating back to almost 10 years ago do not change this opinion, which is shared by anyone who has come into contact with this great champion. 2/2 — JuventusFC (@juventusfcen) October 4, 2018

Since the report, Juventus’ share price dropped nearly 20 percent, according to The Associated Press.

Part of the reason there isn't a bigger outrage in Italy is because "the #metoo movement didn’t really happen here," Salhani said.

"From the left and the right there was a lot of dismissal of the movement," he said. "Italian journalists have told me quietly that they're steering clear (of the Ronaldo story)."

"It’s just not being pushed in front of people’s eyes."

All eyes will instead be trained on Ronaldo on the pitch. He is scheduled to take the field as usual Saturday for Juventus's game against Udinese.

CORRECTION (Oct. 6, 2018, 7:49 a.m. ET): An earlier version of this article misstated the first name of a soccer player. He is Lionel Messi, not Leonardo.