Arsenal restored their five-point Premier League lead over Manchester City with a 3-2 victory over Manchester United on Sunday.
A late strike from Eddie Nketiah gave the Gunners all three points at the Emirates after City had earlier seen off Wolves 3-0 as Erling Haaland netted a fourth hat-trick of the season.
But it was Roy Keane's moustache that had many football fans talking before, during and after the game as the former United captain did punditry on Sky Sports.