The Italian soccer federation has opened an investigation into Roma defender Gianluca Mancini’s celebrations at the end of Saturday’s capital derby which saw the player waving a huge flag in Lazio colors that also had a giant rat painted on it.

Mancini, who said he was “the happiest man in the world” after his goal gave Roma a 1-0 win over Lazio in Serie A, joyously celebrated with the rest of his team in front of the Giallorossi fans but sparked controversy when he was seen waving the flag.

“I didn’t want to offend anyone, I took the first flag they gave me,” Mancini said. “I apologize.”

FIGC president Gabriele Gravina confirmed to Italian media on Sunday that the federation had opened an investigation.

The 27-year-old Mancini faces a potential fine but could also risk a suspension. AP