Barnsley slipped to their second successive defeat thanks to a brace from Glenn Murray.
The Seagulls leapfrogged the stuttering Reds as Paul Heckingbottom’s charges’ two-match winning streak on the road came to an abrupt end at the AMEX.
Bournemouth loanee Murray opened the scoring in minute 12 with his fourth of the season with an easy tap-in after a counter.
The Reds were caught by the searing pace of Anthony Knockaert before Baram Kayal unselfishly squared the ball to Murray who made no mistake from close range.
The visitors failed to cope with the constant pressure of the Seagulls’ wingers as they continuously caused problems after getting in behind the Reds’ backline.
The hosts were good value for their lead as Heckingbottom’s free-scoring side failed to make their mark on the match on the south coast.
Murray missed a glorious chance to double his tally in the first half before captain Conor Hourihane almost scored an own-goal with Adam Davies alert enough to tip his header wide.
Three minutes after the break matchwinner Murray glanced Jiri Skalak’s free-kick home to give the Reds an uphill battle to get back into the match.
Davies denied Murray a well-deserved hat-trick with a sublime save before Adam Armstrong headed wide down the other end.
The visitors’ best chance fell to Josh Scowen who, after a nifty one-two with Sam Winnall, was smartly kept at bay by David Stockdale.
Brighton (4-4-2): Stockdale; Bruno, Duffy, Dunk, Bong; Knockaert, Stephens, Kayal (Norwood 45), Skalak (Sidwell 84); Hemed (Baldock 76), Murray.
Subs: Maenpaa, Hunt, Goldson, Murphy.
Reds (4-4-2): Davies; Yiadom, Roberts, MacDonald, Kpekawa; Hammill, Scowen (Morsy 80), Hourihane, Watkins (Kent 64); Winnall (Bradshaw 80), Armstrong.
Subs: Townsend, Bradshaw, Morsy, Jackson, Kent, Bree, Lee.