In-form Cameron Jerome gave Derby a priceless playoff advantage as they beat Fulham 1-0 in the race to reach the Premier League.
The striker scored his fifth goal in four games to claim a narrow victory for the Rams in Friday's Championship playoff first leg at Pride Park.
Fulham hit the bar through Kevin McDonald and dominated the second half but they must recover on Monday to avoid more play-off heartbreak.
They lost in the semi-finals to Reading last season and also missed out on automatic promotion to Cardiff on the final day this year.
Derby only booked their playoff spot last weekend -- finishing 13 points behind Fulham -- but will go to Craven Cottage ahead after an excellent defensive display.
Ryan Sessegnon and Floyd Ayite were off target for Fulham during an opening half an hour which was low on chances and quality.
The visitors, while they had the bulk of the possession, were sloppy on the ball and Derby's pressing failed to yield a break.
Aston Villa or Middlesbrough await the winner of the tie and neither side would have been particularly fearful.
But Pride Park exploded into life after 34 minutes when Jerome continued his hot streak to hand the Rams the lead.
A smart move eventually found Craig Forsyth on the left and his glorious deep cross was met by the on-rushing Jerome to power a header past Marcus Bettinelli at the far post.
The goal settled the hosts, despite Scott Carson being forced into saving Aleksandar Mitrovic's low drive.
Fulham have failed to win promotion in all three of their previous play-off appearances but nearly levelled nine minutes after the break.
The Cottagers needed to find an extra gear and almost grabbed it when McDonald smacked the crossbar from the edge of the area.
Ayite then volleyed over a minute later but the visitors refused to panic and continued their methodical passing approach.
But Curtis Davies and Andre Wisdom shackled Sessegnon and Mitrovic well, leaving Fulham to rely on efforts from distance.
Carson beat away Tom Cairney's drive after 63 minutes as the Cottagers' threat grew with Derby struggling to escape their half.
The Rams relied on brief breaks to alleviate the pressure but their compact defensive display frustrated Fulham.
Cairney curled wide with four minutes left and the Cottagers now need to break stubborn Derby down in London.