Brighton & Hove Albion will go into Sunday’s play-off semi-final second leg needing to overturn a 2-1 deficit, as Jesse Lingard’s opener was cancelled out by Chris Martin’s penalty and a Tomasz Kuszczak own-goal.
Albion started the match brightly and had a chance within the opening minute, as Lingard and Andrea Orlandi linked up well, but the latter’s cross went over the upright.
County also looked lively on the counter-attack, as Johnny Russell’s cross went narrowly past the far post after some slick football.
But it was Oscar Garcia’s side that took lead in the 18th minute thanks to Lingard. The Manchester United loanee was on the end of some lovely interplay between Orlandi, Will Buckley and Inigo Calderon and fired past Derby keeper Lee Grant at the second attempt.
Albion’s lead last ten minutes as referee Roger East pointed to the spot following Matthew Upson’s challenge on Craig Forsyth.
Martin stepped up and sent Kuszczak the wrong way to net his third goal at the Amex this season.
There were still chances for both sides at the break, as Leo Ulloa forced a good save from Sky man of the match Grant with a close-range header, while Gordon Greer cleared Russell’s cross off the line.
Derby netted a second right on half-time and it had an element of fortune about it as Martin’s shot cannoned back off the crossbar, hit Kuszczak and dropped into the back of the net.
The Rams had a chance to extend their lead moments after the re-start, when Jamie Ward hit Jeff Hendrick’s deep cross into the side-netting.
Albion’s first real chance of the second-half fell to Calderon, after some good work by sub Kazenga LuaLua down the right-hand side found the right-back in space, but he fired over the target.
Orlandi then put in a superb cross for Ulloa, but the Argentine’s header was tipped onto the bar by an excellent Grant save.
Ulloa was involved in the thick of the action again moments later, as he appeared to have his shirt pulled inside the box only for referee East to wave away the frontman’s protests.
Substitute Solly March looked lively after coming on from the bench and delivered a dangerous ball into the box which was almost poked in past Grant by Rams defender Forsyth.
Albion came closer to netting a crucial equaliser in the final 10 minutes as Stephen Ward’s rasping drive forced another fine save by Grant.
LuaLua also had a chance late on from a set-piece, but his effort was blocked and Derby now hold a slender lead ahead of Sunday's game at the iPro Stadium on Sunday.