Wayne Rooney was able to look on the bright side despite seeing his unbeaten run as Derby's interim manager ended by Preston.
The Rams played for 70 minutes with 10 men after Martyn Waghorn was sent off for a reckless challenge on Preston skipper Alan Browne.
And they looked to have earned a precious point until North End produced a moment of quality in the sixth minute of stoppage time, when Browne sent a shot beyond Derby goalkeeper David Marshall and inside the far post to snatch a 1-0 win.
A draw would have been enough to lift Derby out of the Championship relegation zone, but despite the late blow Rooney remained upbeat.
"I think it was the best performance of the season," he said.
"With 10 men for so long we knew it was going to be tough, but I still felt we had a belief about ourselves that we could win the game.
"We had to defend well and dig in, but when we had the opportunity to break I thought we broke well in numbers and looked a threat going forwards at times, and I thought the lads gave everything.
"I thought it was a clear foul on Louie Sibley in the middle of the pitch just before the goal.
"I don't want to slate referees because I know how difficult it is for them, but they are big moments. That decision, he gives the free-kick and if we go into the corner the game's over and we take a very well-earned point.
"He doesn't give it. I'm not blaming him for them scoring but he doesn't give it and we lose the game. It's a clear foul which out of the four officials one of them has to see it."
Preston manager Alex Neil admitted he was a little surprised to see his team take all three points.
"We didn't really move the ball in the second half and, if I'm being honest, in the second half I didn't really see the goal coming," he said.
"I didn't think we moved the ball quick enough, I didn't think we probed enough, and I didn't think we kept the ball at the top end of the pitch well enough.
"But I've been involved in games this year where we've done all that well and still not won, so it's nice when Alan pops up with a little bit of quality and that decides the match.
"I didn't think Derby were going to get a result in terms of a win but, equally, I thought second half we didn't test Derby enough to get the goal.
"I didn't think it was coming but, like I say, Alan produces a bit of quality to win us the match."
