A youthful Town U21 Development side were beaten 4-0 by Brighton, at Lancing FC's Culver Road stadium.
The Seagulls included a number of players with first-team experience in their side and were good value for their win.
Josh Carson was the most senior player in the Blues starting line-up and Town held their own until just before half-time, when the hosts broke the deadlock.
Solly March skipped away from his marker before crossing dangerously from the right, with the unfortunate Joe Whight turning the ball past his own 'keeper Michael Crowe and into the net.
The Town defender then tripped Ben Sampayo in the area, with the referee having no hesitation in pointing to the spot. Thnakfully for Blues, striker Stephen Dobbie fired his effort high over the bar.
However the former Swansea man was to have the final say, as the Seagulls' experience shone through with three late goals.
First Dobbie found Will Hoskins, who calmly netted past Crowe to double the advantage for Brighton, before Dobbie superbly volleyed home with ten minutes remaining to make it 3-0.
The Scottish striker then sealed the win in injury time, chipping home his second and Brighton's fourth to win the game.
Town: Crowe, Hammond, Thorsteinsson, Whight, October, Winter, Burke, Carson, Timlin, Lawrence, Marriott. Subs: Robinson, Thompson, Galvin, Leddy, Willbye.