Southampton looked poised to claim consecutive Premier League victories, but Brighton rallied to draw 2-2.
Pierre Emile Hojbjerg and Danny Ings each scored either side of the break for a dominant Saints, but Shane Duffy’s quick response goal was the catalyst for disappointment at St Mary’s.
Glenn Murray then punished Saints, who have made a habit of letting leads slip through their grasp, from the penalty spot in added time.
Southampton provided an instant spark during a dominant first half performance and nearly nudged ahead on 21 minutes from a goalmouth scramble, only for Ings to be denied from point-blank whilst Wesley Hoedt fired the rebound over.
Mohamed Elyounoussi failed to turn in Redmond’s cross, as the winger was left alone to head wide of the post with Saints the closest to an opening goal.
But Hojbjerg took advantage of all the pressure when his wondrous strike from distance found the bottom corner to make it 1-0 and raise the level of excitement inside the ground.
Ings would double the advantage after the restart from the penalty spot, despite the goalkeeper guessing the right way, moments after drawing the foul against Gaeten Bong.
Southampton’s two-goal lead lasted just 129 seconds, however, as Duffy pulled Brighton back into the match with a header that caught a flat-footed Alex McCarthy.
Brighton, who had responded emphatically after falling behind by a pair of goals, nearly drew level but substitute Alireza Jahanbakhsh found the outside of the goal with 10 minutes remaining.
Still in control of securing all three points, Southampton hunkered down and evaded chances from Brighton, including a save from McCarthy late on.
Though a defensive error from James Ward-Prowse had the referee Anthony Taylor pointing to the spot, deflating Saints’ spirit.
Murray sent his penalty kick straight down the middle to the chagrin of the Southampton support.
Ryan Bertrand had one last opportunity to restore Southampton’s lead from a free-kick, but Mat Ryan was equal to the attempt.
Southampton: McCarthy, Bertrand, Hoedt, Vestergaard, Cedric, Lemina, Hojbjerg, Elyounoussi (Ward-Prowse 76), Redmond, Long (Gabbiadini 76), Ings (Davis 84).
Unused subs: Gunn (GK), Yoshida, Targett, Austin.
Goals: Hojbjerg (35), Ings (65 PEN).
Bookings: Cedric (56), McCarthy (86).
Brighton: Ryan, Montoya, Duffy, Dunk, Bong, Knockaert, Stephens, Propper, March (Jahanbakhsh 71), Bissouma (Locadia 76), Murray.
Unused subs: Button (GK), Balogun, Bruno, Bernardo, Kayal.
Goals: Duffy (66), Murray (90 PEN).
Bookings: Stephens (77), Knockaert (90+1), Locadia (90+2).