Arsenal were denied a crucial stoppage-time equaliser against Aston Villa after Kai Havertz was spotted to have handled the ball in the penalty area.
The Gunners thought they had levelled the match in the closing minutes at Villa Park when Havertz crept in at the back-post and turned the ball into the net.
However, the German was quickly denied what would have been a huge goal in the Premier League title race when Australian referee Jarred Gillett blew his whistle to disallow the goal.
Confusion quickly reverberated around Arsenal's ranks with Mikel Arteta's side believing they had snatched a point at one of the toughest grounds in the English top-flight before having the goal cancelled out.