Roy Keane was allegedly assaulted by a fan inside the Emirates Stadium on Sunday as he made his way to do his post-match duties for Sky Sports.
Mail Sport understands the 52-year-old former Manchester United captain was confronted by a man at the top of the West Stand as he was waiting for a lift to take him down to the pitchside area.
The man allegedly aimed a headbutt at Keane and hit the Irishman on the chest and chin, but was prevented from inflicting serious physical damage.
Footage circulating on social media last night showed Keane's Sky Sports colleague Micah Richards grappling with the man to restrain him, but the supporter had left the vicinity before security guards arrived.
The incident happened shortly after Alejandro Garnacho had looked to have won the contest for United in the 88th minute.
Keane and Richards, who were working with former Arsenal player Theo Walcott, had raced back to the studio to see what had happened, with Garnacho's goal eventually being ruled out after a VAR check.
Keane, who had a tempestuous relationship with Arsenal during his playing career, was eventually escorted down to the pitchside area where he continued broadcasting.
A Sky statement sent to Mail Sport after the match revealed that the police are now investigating the alleged assault that saw Richards attempt to defuse the situation.
'We understand the police are investigating an alleged assault by a member of the public immediately preceding the footage circulating on social media.
'In the footage seen, Micah Richards was acting to defuse a situation.'
Sunday's match reached boiling point before the full-time whistle, with the Emirates a cauldron of noise after an eventful 113 minutes of action.
Marcus Rashford opened the scoring for United as they went ahead against the run of play by scoring on the counter-attack against a perilous Arsenal side.
Their joy was short-lived as Arsenal replied with an equalizer just 35 seconds later and finally, the rivalry between two great rivals was reignited.
