The television presenter has criticised the Newcastle United striker on social media.
A divisive character - both Keys and Mitrovic - the television presenter made his feelings on the Newcastle striker clear, comparing him to Chelsea's Diego Costa but implying that he gets away with far more.
Keys was referring to an incident in the second half, which was the same 45 minutes that saw Steve McClaren's men go from drawing 1-1... to losing by five goals.
If Costa does what Mitrovic has just done at City there'd be questions in Parliament. Wait till you see it.— Richard Keys (@richardajkeys) October 3, 2015
However, despondent Newcastle fans may have been distraught over their side's result but they weren't prepared to hear Keys' criticism of the striker.
Indeed, they simply felt Mitrovic was acting fairly and he was a bright spot during an encouraging first half for the Magpies.
Is it time for McClaren to go? If his kind of team-talks can take a positive performance and turn them into a 6-1 defeat, it's probably time to call time on an increasingly bad career in football management.
@richardajkeys no way you got that wrong keys he turned and his arm caught him— Chris Rayne (@chrisrayne1) October 3, 2015
@richardajkeys is this a wind up? Anyone that has played football can see thats just normal movement regardless of who does it.— Alex Patterson (@alexpatta) October 3, 2015