Patrick Bamford’s second-half goal condemned Albion to their first defeat of 2014 in a tight affair at the iPro Stadium.
In a contest of few chances the game was decided on a moment of quality from the Chelsea loanee.
Keith Andrews dragged a shot wide within 60 seconds but fans had to wait until the 22nd minute for the next effort on goal as both teams cancelled each other out in the early stages.
It was Jamie Ward who provided it after breaking through Albion’s midfield line, however his curled attempt skewed harmlessly wide.
Neither keeper had been tested in the opening 25 minutes but Lee Grant had to be at his alert best to tip Matthew Upson’s bullet header over from Andrea Orlandi’s corner.
Under Steve McClaren the Rams have been revived this season, and their quality began to tell on the half-hour with a spell of pressure, but Brighton’s rearguard prevailed.
All square at the break and the second half started in similar fashion with chances at an absolute premium for both sides.
The first real sight of goal came on 57 minutes when David Lopez’s cross dropped for Orlandi at the back post but Andre Wisdom charged down the midfielder’s drive.
Chances continued to be limited with defences on top until substitute Bamford pulled a rabbit out of a hat with a long range strike on 76 minutes on his home debut.
The striker latched onto a loose ball just outside the Albion box, unleashing a dipping effort past the diving Tomasz Kuszczak.
The goal opened the game up and Leo Ulloa forced Grant into a sprawling save with a quick strike on the turn, although there were muted appeals for a penalty for holding on the Argentinian forward.
Oscar’s side tried to put some late pressure on the Derby defence but it was McClaren’s men who collected the spoils.