Relegated Leeds ended their stay in the Championship as Derby ran out winners.
The game was delayed for 10 minutes early on when referee Phil Crossley was taken to hospital with a back injury after he was floored in a collision.
Derby, guaranteed to finish third, went 1-0 up in first-half stoppage time when Seth Johnson set up Darren Currie.
Leeds' Robert Bayly was then shown a straight red card for attempting to head-butt Craig Fagan, before Tyrone Mears added a second late on.
Derby manager Billy Davies, looking ahead to the play-offs:
"People can talk up these games as much as they like, but it does not matter to me who we play.
"There will be no changes to our routine this week in terms of preparation and there will be no trips to fancy hotels.
"We will go to Southampton looking to take the game to them and score goals."
Leeds assistant boss Gus Poyet on Bayly's dismissal:
"I do not think Robert deserved to be sent off. Too many referees do not know what it is like to be a footballer.
"Robert was not trying to head-butt someone, he was trying to show he was strong in front of an opponent."
Derby: Bywater, Mears, Leacock, Nyatanga, McEveley, Bisgaard (Currie 45), Pearson, Seth Johnson, Peschisolido (Lupoli 80), Howard (Macken 67), Fagan.
Subs Not Used: Michael Johnson, Malcolm.
Booked: Peschisolido, McEveley.
Goals: Currie 45, Mears 86.
Leeds: Ankergren, Rui Marques, Robbie Elliott, Foxe (Tom Elliott 46), Gray, Carole (Howson 53), Thompson, Bayly, Cresswell, Johnson, Blake (Delph 52).
Subs Not Used: Stack, Moore.
Sent Off: Bayly (72).
Booked: Thompson, Robbie Elliott, Cresswell.
Ref: P Crossley (Kent).