James Tilley scored the only goal of the game as Albion were made to work hard by League Two Barnet to reach the third round of the Carabao Cup this evening.
Sussex youngster Tilley, who came on at half-time, fired home the only goal on 53 minutes after Liam Rosenior's shot was blocked.
The visitors had to make a change in goal before kick-off as Craig Ross replaced Jamie Stephens, who was injured in the warm-up.
Barnet's Mauro Vilhete sent two efforts off target in the opening 20 minutes, while the closest Albion went was when Tomer Hemed poked the ball wide from 12 yards as the game got off to a quiet start.
The Seagulls had a great chance to go ahead just past the half hour as Anthony Knockaert won possession off Ricardo Santos to get clean through on goal but Barnet keeper Ross denied the winger.
The visitors' Jack Taylor curled a 20-yarder just past the post on 38 minutes, before Barnet had penalty appeals waved away when Shaquile Coulthirst went down under a challenge from Albion keeper Niki Maenpaa.
Brighton made two changes at the break as Tilley and Ales Mateju replaced Gaetan Bong and Knockaert, who was booked after the half-time whistle blew for berating an assistant referee for a good 30 seconds when he was not given a free kick.
Brighton took the lead eight minutes into the second half when captain Rosenior broke into the penalty area and after his shot was blocked, Tilley drilled the rebound home from 12 yards for his first senior goal.
The visitors almost levelled shortly afterwards but Maenpaa made an outstanding save to keep out Jamal Campbell-Ryce's close-range header and Santos headed the rebound into the side netting.
Barnet continued to press for an equaliser and Jean-Louis Akpa-Akpro drilled an effort against the post on 70 minutes, before Albion sent on 17-year-old Aaron Connolly for Tomer Hemed with 15 minutes to go.
The Bees continued to push forward but Albion held on to record their first win of the season.
ALBION: Maenpaa; Rosenior, Goldson, Huenemeier, Bong (Mateju 45); Knockaert (Tilley 45), Molumby, Ince, Skalak; Towell; Hemed (Connolly 75). Subs: Ryan, Dunk, Propper, Ahannach.
BARNET: Ross; Clough, Santos, Campbell-Ryce (Akinola 64), Coulthirst (Amaluzor 70), J.Taylor, Tutonda, H.Taylor, Fonguck, Vilhete, Akpa-Akpro (Bover 76). Subs: Kyei, Shomotun, Smith.