Cristiano Ronaldo faced a flurry of criticism after appearing to make an obscene gesture following the end of Al Nassr's 3-2 win over Al Shabab in an exciting Saudi Pro League game on Sunday.
The Portugal forward opened the scoring with a 21st-minute penalty but Al Nassr needed a late goal from Brazilian Talisca, who struck twice, to settle the game with four minutes left.
After the final whistle, social media videos captured Ronaldo cupping his ear before repeatedly pumping his hand forward in front of his pelvic area. The action appeared to be directed at the rival Al Shabab supporters.
In the background, chants of "Messi" could be heard, referencing Ronaldo's long-term football rival from Argentina.
The incident was not caught on television cameras, but some Saudi pundits said Ronaldo should be sanctioned.
There has been no official response but Saudi newspaper Asharq al-Awsat said the national football federation (SAFF) had opened an investigation into the incident.
"The disciplinary committee is facing the biggest test. We will wait and see," Waleed Al Farraj, a prominent Saudi writer and television host, said on social media platform X.
"Everything has its limits, no matter how famous you are. This is how the major leagues are."
Al Nassr were not immediately available to comment.
The 39-year-old Ronaldo has faced similar criticism in the past. In April last year, he appeared to grab his genitals while on his way to the dugout following the end of a league game against Al Hilal, which Al Nassr lost 2-0.
Earlier this month, he picked up an Al Hilal scarf thrown at him from the stands, put it in his shorts and then threw it away as he walked towards the tunnel after Al Nassr lost 2-0 in the Riyadh Season Cup final.
Ronaldo, who joined Al Nassr as a free agent in late 2022, tops the Saudi league scoring charts with 22 goals in 20 appearances so far this season. Al Nassr are second in the table with 52 points, four behind Al Hilal, who have a game in hand.