"Derby coped better with the type of game it was and that is a lesson to these young players," he admitted after Rob Hulse's late winner.
"We had too many at five and six out of 10 today.
"But am I going to criticise these players? Not a chance. I am very proud of what they have done so far this season - they have been top class."
Rams coach and former Reds star John Metgod wants his side to kick on from their victory.
"This is the benchmark," he said.
"We have had it before against big teams and then the next game has been totally different."