Any tentative signs of a turnaround in Forest's fortunes taken from Saturday's scrappy win at Watford were blown away within 45 minutes.
Steve McClaren's side went in at half-time trailing by four goals to nil and the former England boss, famously pictured on the Wembley touchline under an umbrella, gave the photographers another golden shot by sitting forlorn in the visiting dug-out as his side were sent back on to the pitch to prolong their embarrassment.
Ishmael Miller's second-half goal was little more than a consolation and Burnley finished the game in style with Charlie Austin scoring a fifth.
McClaren has protested loudly about the lack of new signings made since he took over at the City Ground but, as with the recent home defeat by Derby, knows that results like Tuesday night's come down to him and his players alone.
He pulled no punches afterwards, saying: "At the end of the day, players cross the white line and they have to be responsible for performance so, yeah, we sent them out early at half time.
"It's for other people to decide about my job. But it's not about me or my job, it's about the team and, as normal after a defeat like that, we ask for a reaction.
"My assessment? Rubbish. Unacceptable for the fans who travelled.
"I didn't see it coming but it seems to be the story of the season - one step forward and three steps back. It's hurting us."