Mourinho was pictured punching the air in delight after watching Valencia score Manchester United’s third goal in the 93rd minute of stoppage time and then heading immediately down the tunnel.
The Portuguese coach did not appear to shake the hand of Middlesbrough boss Steve Agnew as he disappeared from view before the final whistle.
And Crooks was less than impressed by Mourinho’s behaviour on the touchline towards the end of the 3-1 win for his side.
Crooks wrote in his column for BBC Sport: “To see United boss Jose Mourinho disappear down the tunnel before the final whistle shaking both fists in total delight at the apparent three points was for me utterly shameful.
“What happens to head coach Steve Agnew in future, or Middlesbrough Football Club for that matter is, at this moment, in the balance but Agnew did deserve to receive a handshake from the Manchester United manager at the end of the game as tradition demands.
“This is Manchester United Football Club and it has a long and proud history of doing things properly.
“I hope the United Board have the courage to remind their employee who he represents.
“Sir Alex Ferguson, with all his tantrums, always respected the traditions of the game and would never have behaved in such a manner.”
Manchester United’s win moved them up into fifth place in the Premier League table as they bid to secure Champions League football for next season.
The Red Devils are next in Premier League action after the international break, when they host West Brom at Old Trafford on 1 April.
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