Adam Webster's own goal condemned Roberto De Zerbi to his worst league run with Brighton as Sheffield United escaped the bottom of the table with a 1-1 draw against 10-man Albion.
Simon Adingra had put the Seagulls ahead with a brilliant solo run but Mahmoud Dahoud's red card saw momentum shift before Webster slid into his own goal.
Brighton, who beat European giants Ajax on Thursday, are now winless in the Premier League in six matches, the longest boss De Zerbi has gone without a victory since arriving on the south coast last year.