Liam Rosenior bemoaned the “most difficult night” in offering no defence of his Chelsea players after they slumped to a 3-0 defeat by Brighton.

“By far,” Rosenior replied when asked if this was the toughest day of his short Chelsea tenure. Questions of whether he survives in his position as head coach until Sunday’s FA Cup semi-final with Leeds will be floated after his team’s abject performance.

Rosenior said after Chelsea’s fifth consecutive league defeat without scoring: “That was unacceptable in every aspect of the game. Unacceptable in the attitude. I keep coming out and defending the players, but that’s unacceptable tonight.

“Something needs to change drastically right here, right now. We need to look in the mirror. I can’t keep coming out here defending some of the things we’re seeing. General attitude, spirit, was lacking, determination, maybe three or four out of the 11, that’s nowhere near enough for this club. I can’t come out and lie, that was an unacceptable performance for this club.”

Goals from Ferdi Kadioglu, Jack Hinshelwood and Danny Welbeck did the damage for a rampant Brighton against a Chelsea team without Cole Palmer, initially playing in an unfamiliar 3-5-2 formation.

Rosenior’s postmortem was stark: “Nowhere near the levels, not even tactical, tackles, duels, intensity, spirit, energy, passion all lacking and that is the reason we lost. I feel numb. I’m so angry. I always speak on what I see and that was unacceptable. The goals we conceded were unacceptable and that is something I have to hold my hands up to.”

The former Brighton player and coach said: “The performance, in terms of professionalism, wasn’t there. It’s a really, really difficult night. The most difficult night here at this magnificent club in my career. Some of the things I was witnessing today, I never want to see again.”

Brighton leapfrogged the visitors in sixth place, closing on a return to European football next season. Their head coach, Fabian Hürzeler, said of their rise up the table: “It is not that important for us. We must keep focusing on performance and keep focusing on what we can do right. We have high expectations of ourselves.”