The result has heaped the pressure on Magpies boss Steve Bruce with fans demanding managerial change at St James’s Park.
But Bruce has vowed to fight on at Newcastle United after an abject defeat for his team at the Amex Stadium.
The club has won just two out of its last 20 games in all competitions – and the position of United's head coach looks to be untenable.
Asked what the defeat meant for his position at the club, Bruce said: “Well, as I’ve always said, that’s for other people to answer, but the one thing that I won’t ever do is give up on anything, as we’ve had a bad defeat.
We’ve been OK, I believe, we haven’t been sensational over the last few weeks, but we have to accept, I have to accept, the criticism that’s going to come our way and the fallout from it, because we were simply nowhere near good enough on a big occasion. We simply haven’t done enough.
"Of course, the buck stops with me. It always does, and I have no problem (with that), because of the way we played, I fully understand the frustration and disappointment of everybody, and rightly so.”
Here, the Gazette’s chief Newcastle United writer Miles Starforth delivers his player ratings after watching the game at the Amex Stadium:
5. Paul Dummett - 5
Offered some resistance at left-back, limited Brighton's chances down his side Photo: Mike Hewitt
6. Jonjo Shelvey - 4
Did some early defensive work, but ill-suited to this position in front of the back four Photo: Clive Rose
7. Isaac Hayden - 6
Stretchered off in agony with what looked to be a bad knee injury after an accidental clash with Bissouma Photo: Clive Rose
8. Joe Willock - 3
Not an influence on the game, taken off in the second half Photo: Clive Rose