Birmingham City eased to victory in a lunchtime kick-off at the City Ground with a three-goal salvo in the ten minutes before half-time making the second-half merely a battle to restore lost pride for the Reds.
Britt Assombalonga netted a comsolation in the final moments but plenty among the 26,212 crowd had departed the stadium before then.
With the Championship sacking season having begun early and continued into Christmas, Stuart Pearce is now under fierce pressure for his job despite the esteem he is held in by Forest supporters.
His side are likely to end 2014 in the bottom half of the table depending on results in the later games and an FA Cup trip to face Rochdale at the weekend will not be an enticing prospect.
Speaking to BBC Radio Nottingham after the game, Pearce said: "We had enough efforts on the opposition goal to win a couple of games, never mind one. But we conceded three horrible, horrible goals and paid the price for that.
"We are lacking leadership and confidence. We spoke to the players after the game and said: 'It is time to roll our sleeves up, gentlemen, and man up.'"