Accepting all of the criticism that came the Reds' way after 'letting the fans down', the City Ground boss downgraded his assessment of the task in hand from a 'work in progress' to a 'big work in progress' but also said: "I hope this is the lowest we can go at Forest."
While prepared to take his share of the blame for Saturday's defeat, McClaren also made it clear that work needs to be done 'on and off the field' for the situation to improve significantly.
While there appears to be plenty of support still for the view that the former England manager has been 'missold' the Forest job on the basis of promises that are not being kept, losing a goal lead when playing with a man advantage for virtually the entire game cannot be blamed on external factors.
'Unacceptable' was McClaren's view and if he is to keep his end of the bargain and restore his own reputation in English football then he cannot afford to have another afternoon like it.