The Eagles were on course to follow up Wednesday night's epic 2-1 victory at Manchester United in the Carling Cup with their first npower Championship win in six but an own goal from skipper Paddy McCarthy sent Derby home with a 1-1 draw.
"Football never goes your way all the time," said boss Freedman. "Paddy has played two games in two days and given his all. He's a great guy with a great attitude."
He added: "I'm over the moon with a point and a semi-final in 48 hours. I've no complaints about the way we played tonight.
"It's been fantastic, a wonderful two games with millions watching us on television."
The hosts got their goal after a quarter of an hour. Peter Ramage robbed Jamie Ward and squared the ball to on-loan Norwich forward Chris Martin, whose 20-yard shot spun off Shaun Barker to leave Frank Fielding wrong-footed.
But Derby, dismal in the first half, were much-improved after the interval and Jason Shackell and Tamas Priskin went close before McCarthy's moment to forget. In the 75th minute, Paul Green swung a cross over and McCarthy clearly lost his bearings, sticking out a foot to clear but succeeding only in diverting the ball past Julian Speroni and into his own net.
It meant the Rams avoided a sixth straight defeat - which would have equalled their worst run since they crashed out of the Premier League four seasons ago.
"We had to stop the rot somehow and it's nice to do it in such a positive way tonight," said Rams boss Nigel Clough. "We had a horrid November, so it's nice way to start December.
"We wanted to play with more conviction in the first half. If we'd started the game like we started the second half we'd have been okay."