Substitute David Ball scored a late equaliser as Peterborough denied Derby a deserved final-day victory.
The Rams started well with Steve Davies forcing two fine saves out of Posh keeper Paul Jones before Theo Robinson touched in Craig Bryson's cross.
But Ball levelled with nine minutes remaining, curling a right-foot shot past Adam Legzdins after racing clear.
George Boyd then shot against the post for Posh, while Davies's header was tipped away by Jones.
The save capped a decent game for the Posh stopper and denied Derby a 12th home victory of the season that looked likely even before Robinson scored his 12th of the season.
Jones had already saved well from Rams leading scorer Davies before tipping his well-struck free-kick past the post.
But he was powerless to stop Robinson, who got in front of his marker and nudged in Bryson's centre with the slightest of touches.
Bryson almost played in Davies for a second before the break, but the ball fizzed harmlessly across goal.
The home side could not convert their dominance into goals though and Posh came close to levelling when Lee Tomlin's left-foot striker trickled inches wide.
Bell finally did equalise before the late excitement which could have seen either side snatch victory.
Derby manager Nigel Clough:
"With the general play and some of the chances we've created and we only get one goal out of it, it probably just highlights the need for somebody to put the ball in the net on a regular basis, that's all that's missing.
"We can get players to put the ball where we want it to be put, Nathan (Tyson) put a couple in there today and we keep asking our strikers to get in there, but we can only ask them for so long."
Peterborough manager Darren Ferguson:
"I'm delighted with where we've finished, because today we could have fallen a few places.
"And I didn't want it to be the case of if other results had gone against us and we finished fourth bottom then people may suggest it's only because Portsmouth got deducted points, so we've done our job and all credit to my players for that."