Referee Mark Clattenburg apologised to Hull City players at half-time after allowing Alexis Sanchez's controversial handball goal to stand.
Arsenal star Sanchez clearly handled the ball into the net to open the scoring at the Emirates Stadium on Saturday afternoon.
Clattenburg appeared to consult his linesman after the ball was put in, and it was assumed the goal would be ruled out.
But it was eventually given, a verdict which sparked outrage on social media, and Tigers defender Andy Robertson has revealed the match official admitted to the Hull team he had made a mistake.