Ryan Sessegnon continued his remarkable scoring run as Fulham won 2-1 at Pride Park to go above Derby in the Championship.
The 17-year-old scored his 10th goal in 12 league games after Aleksandar Mitrovic had put Fulham ahead in a first half dominated by the London side.
Derby hit back through Tom Huddlestone and could have snatched a point in stoppage time, but with Tom Cairney delivering a fine display in midfield the visitors deserved their 10th win in 13 matches.
The first chance fell to Fulham in the fourth minute when the ball broke to Sessegnon 10 yards out on the left but Scott Carson got down well to save at his near post.
Derby swept upfield and Andre Wisdom whipped in a low cross from the right which Andreas Weimann turned in only to be denied by an offside flag.
Fulham were ahead in the 10th minute when a corner was lobbed back in by Stefan Johansen and the ball bounced off Craig Forsyth for Mitrovic to beat Carson from eight yards.
Derby responded well with first Cameron Jerome having a shot blocked by Denis Odoi before Kevin McDonald got across to take the ball away as the former Norwich striker was poised to strike.
Wisdom fired wide after cutting in from the right in the 17th minute but Fulham scored again in the 22nd minute when Johansen's back-heel wrong-footed the defence and Sessegnon drove a shot across Carson and inside his left post.
Fulham were close to a third when Floyd Ayite had a shot charged down by Wisdom and Mitrovic saw a shot flash just wide in the final minute of the first half.
The Serb striker had another chance in the 52nd minute when a Matt Targett cross was deflected into his path at the back post but he stabbed the ball wide.
Cairney was running the game but Derby were back in it in the 68th minute when a Tom Lawrence free-kick was headed across the face of the area and Huddlestone took a touch inside before firing a low shot into the bottom left corner.
Fulham almost gifted Derby an equaliser in the 78th minute when Marcus Bettinelli spilled the ball as he tried to collect a defensive header but Lawrence's follow-up was blocked by Tim Ream.
Derby twice went close in stoppage time as first Lawrence had a shot deflected behind by McDonald and then Bettinelli turned over a Richard Keogh drive but Fulham held on for another victory.
Gary Rowett: "Certainly from the start of the game we were very, very good, very aggressive and made it difficult for Fulham to play out. But once again, the reality is we made two very poor mistakes for the goals and from starting the game really well, we are 2-0 down at home.
"If I'm being honest, in the 10 minutes before half-time we looked a bit sorry for ourselves, two or three players had their heads down and we started to feel it wasn't going to be our day and I don't want that. I've got no time for that, we have to show fight."
Slavisa Jokanovic: "I started working with him when he was 16 years and two months or something like that and I believe he can be part of the English national team for the World Cup. I cannot recommend him to people but nobody can make mistakes with this kid. Experience is important but he is a really expert player for his age at this moment.
"I will repeat, if the national team don't take this decision this time, they will push him for the next European tournament. It's evident that if he doesn't have any injury problems, he will be a top player. He is not a kid, he is a man and he gives myself, the club and his team-mates many things and we try to support him and make him still better than he is right now."