The Seasiders were conquerors of West Brom in Round Three but Neil Critchley’s side found themselves just edged out on the south coast.
Brighton did create the better chances earlier on as defensive pair Lewis Dunk and Adam Webster both nodded over.
And just as the Seagulls looked to be finally exerting control, midfielder star Yves Bissouma crashed home a magnificent opener.
However, despite struggling to make any inroads in the first 45, Blackpool levelled before the break, as Gary Madine scrapped home Luke Garbutt’s cross.
But Brighton refused to be deterred after the restart as Steven Alzate curled home a brilliant second.
Graham Potter’s side probably could and should have made it safe in the final 10 minutes as Neil Maupay tested Chris Maxwell but in the end they had enough to squeeze over the line.
Full Time from the AMEX Stadium it’s Brighton 2 Blackpool 1