Goals from Clinton Morrison and Mark Kennedy put Sunderland and Birmingham into the Premiership as Crystal Palace comfortably saw off a woeful Derby.
Morrison was a constant threat for Palace
Morrison's composed finish from just inside the area put the hosts ahead.
Then, with Derby hardly threatening Julian Speroni's goal, Palace doubled their lead as the Rams capitulated.
Kennedy took advantage of some atrocious marking to fire past Lee Camp at his near post and condemn below-par Derby to the Championship play-offs.
Despite Palace having nothing but pride to play for, they caused the visitors problems throughout and should have taken the lead inside the first 10 minutes.
Dean Leacock's misjudged header fell to Morrison, who stabbed his close-range half-volley just wide.
Palace's leading scorer, who spent three years with Birmingham, made amends for his earlier miss with a neat finish from just inside the area on 29 minutes after Carl Fletcher's mis-hit shot had landed at his feet.
The Rams, looking lethargic, failed to test Speroni until the 38th minute when both Matt Oakley and Steve Howard shot straight at the keeper.
When Giles Barnes, their most inventive player, hobbled off with a knee injury five minutes after the restart, the visitors looked totally bereft of ideas.
Palace continued to stretch Derby's dishevelled defence with Ben Watson and Jobi McAnuff wasting close-range chances when clean through.
But the London side doubled their lead when awful defending allowed Kennedy the time and space to run at goal before hitting a shot that beat Camp at his near post.
Derby's beleaguered defenders squabbled in the aftermath of the goal, while the forwards flattered to deceive going forward.
Substitute Arturo Lupoli was denied a late consolation by a fine, low save from Speroni, but a goal would have been more than the visitors deserved.
Crystal Palace boss Peter Taylor:
"There was a lot of pressure on Derby today, because they knew they had to win the game.
"Some of their play was excellent, though. They are a very good team and play a really good system.
"They will possibly be the favourites to go up through the play-offs. We are as good as Derby, but we are not as consistently good as they have been."
Derby manager Billy Davies:
"It was all about handling the occasion, and we did not get a grip of the pressure we had to face. Palace came out with nothing to play for. It was a Sunday stroll for them: no pressure, no problem.
"But now I can rest players in the final league game, and there is time to patch up one or two more before we go into the play-offs.
"I am disappointed with the result, but very proud of where we have come from. Automatic promotion was one step too far, but I am proud as a manager to have reached the play-offs three seasons in a row, with two different clubs."
Crystal Palace: Speroni, Lawrence, Hudson, Cort, Borrowdale, McAnuff, Watson, Fletcher, Kennedy, Morrison (Ifill 77), Kuqi (Scowcroft 74).
Subs Not Used: Kiraly, Freedman, Butterfield.
Goals: Morrison 29, Kennedy 67.
Derby: Camp, Edworthy (Mears 46), Leacock, Nyatanga, McEveley, Teale, Jones, Oakley, Barnes (Lupoli 51), Currie (Fagan 65), Howard.
Subs Not Used: Grant, Pearson.
Ref: T Bates (Staffordshire).