Michael Oliver is so biased against Arsenal that he's now giving "soft" decisions against former Gunners players in the Champions League.
Oliver initially did not punish Roberts for the challenge, later sending him off following a review using a pitchside monitor.
Referee Michael Oliver has not been assigned a Premier League match this weekend. Oliver last officiated the FA Cup fifth-round tie between Crystal Palace and Millwall. He failed to stop play after Palace striker Jean-Philippe Mateta was kicked in the head and suffered an injury.
The Premier League referee was involved in Champions League action in midweek with some big decisions for him to make.