Sunderland’s fiery boss let rip with an amazing rant after being invited in for a Christmas drink following Saturday’s controversial 2-1 defeat at the Madejski.

A Reading player said: “It was incredible. Roy was absolutely steaming. And at the time no one had a clue why.

Roy would naturally have been disappointed at the way the game ended — but that is not our fault.

“He was invited into the gaffer’s office for a drink, which is the normal act of courtesy here.

“But, within 10 seconds of going in there, all hell seemed to break loose. He was fuming and really having a go at everyone in there as if it was his office at Sunderland.”

Reading boss Coppell was absent but Keane stunned backroom staff with his outburst which included accusing them of ‘disrespecting Sunderland’.

A club official was eventually forced to manhandle Keane out and into the players’ tunnel.

Sunderland were sunk by a controversial injury-time winner which — they claim — did not cross the line and puts the club into the Premier League’s bottom three going into a crucial phase of the season.