Declan Rice apologised to West Ham's fans after the dismal 4-0 defeat at Brighton.
The struggling Hammers appeared to have turned a corner when they thumped Nottingham Forest 4-0 last weekend before running Manchester United close in the FA Cup.
But they came horribly unstuck on the south coast as a penalty from Alexis Mac Allister, tap-ins for Joel Veltman and Kaoru Mitoma and a late strike from Danny Welbeck left them in the thick of the relegation battle.
'It's a cliche to say it was not good enough but you have to apologise to the fans because we have let them and the club down,' skipper Rice told the club website.