Nigel Clough admitted his team fluffed their lines as QPR tore up the script with a 2-0 victory at Pride Park.
Clough's first game in change of Derby ended in a deflating defeat against a Rangers side who celebrated their first away win under manager Paulo Sousa.
First-half goals from Wayne Routledge and Mikele Leigertwood were enough to ruin Clough's big day at the club where his famous father Brian made his name. Asked if he was bitterly disappointed, Clough admitted: "Those two words are quite fitting."
He added: "We started quite brightly but we were in possession both times for the two goals we conceded.
"You can only do so much to get a positive feeling around the place but when that first goal goes in everything reverts to type and that's something we have to deal with.
"A few players were below par and people didn't do their jobs.
"The strikers didn't hold the ball up and the wide men didn't get crosses in, the sort of things we got used to at our previous club (Burton Albion)."
For Rangers the victory was the perfect response to their FA Cup exit at Burley in midweek, when they were beaten by a goal in the last minute of extra time.
The only negative note was a serious injury to skipper Martin Rowlands, who was carried off on a stretcher after only 12 minutes.
Sousa said: "I want to dedicate this victory to him. He always wants to win, he is a fighter, our captain and our leader. We could have lost him for the season. We think there is a problem in one of his knees, we will know more later but if we have lost a player we have not lost a person."
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