Derby County Under-23s suffered a 4-1 defeat to Brighton & Hove Albion in Premier League 2 at Moor Farm Training Centre.
Jahmal Hector-Ingram had given Derby an early lead, but three more first half goals gave Brighton a 3-1 lead at the interval.
Taylor Richards added a fourth from the spot midway through the second half to secure the three points for the visitors.
The Young Rams were quickest out of the block in tricky conditions, as Hector-Ingram powerfully struck home his tenth Premier League 2 goal of the season, leaving Jason Steele with no chance.
Derby continued to push forward following the goal, with Alex Babos, Rushian Hepburn-Murphy and Cameron Cresswell all going to close to doubling the Young Rams’ lead.
Brighton grew into the game and got a leveller midway through the first half thanks to Peter Gwargis’ first of the afternoon.
Berem Kayal played the ball forward for Romaric Yapi, who did excellently to keep the ball in play and square for Gwargis who finished well from close range.
Gwargis added his and Brighton’s second on the half hour mark, after slotting home from Alex Cochrane’s set from the left.
Teddy Jenks gave Brighton a two-goal cushion going into the break as he struck an unstoppable low effort - from Kayal’s set - past Henrich Ravas in the Derby net.
The Young Rams looked to cut the deficit early in the second half, but Cresswell’s header crashed off the woodwork following a superb near post corner from Babos.
Derby kept looking for a way back into the game, but those hopes were removed as Brighton were awarded a penalty with 20 minutes left on the clock.
Substitute Richards, who got on the end of Lorent Tolaj’s reverse pass, was brought down by Ikechi Anya for the spot kick. Ravas saved the first effort, reacted quickest to finish the rebound.
The defeat leaves the Under-23s in fourth spot and four points behind third-placed Albion.
Derby: Ravas, Anya, J.Brown, Dixon (L Thompson 69), Wassall, Minkley, Hepburn-Murphy (A.Brown 45), Babos, Hector-Ingram, Cresswell, Shonibare.
Subs not used: Foster, Sephton, Stretton.
Brighton & Hove Albion: Steele, A. Davies, Cochrane, Crofts, O’Hora, Roberts, Yapi (Spong 81), Jenks, Gwargis (Richards 66), Kayal (Tolaj 45), J. Davies.
Subs not used: Desbois, Tsoungui.