Anton Forrester rescued a draw for Bury with an injury-time header against a Southend side that finished with 10 men.
Ben Coker put the Shrimpers in front with a curling first-half free-kick, then was sent off for two late bookings.
Within four minutes of the defender's dismissal, Forrester levelled with a header from Jordan Sinnott's cross.
However, the result ended Southend's four-match losing streak.
VIEW FROM THE DRESSING ROOM
Southend United manager Phil Brown told BBC Essex:
"We're on the field of play there with a team that hasn't caused us any problems at all. Every problem has been caused by ourselves.
"I can blame referees, I can blame linesman, I can blame red cards, but I don't want to blame them, I want to blame ourselves.
"Naivety. Unprofessional. Almost a bunch of children making wrong decisions. It's so frustrating, so frustrating.
"Bottom line is we've thrown away two very, very, valuable points and if these players don't start learning very, very quickly, we're going to have to change them. It's as simple as that."
Bury 01 Carson 02 Beeley 03 Roberts Booked 05 Cameron 25 Edjenguele 06 Procter 07 Jones 08 Miller (Sinnott - 78' ) 19 Soares (Reindorf - 46' ) 09 Forrester 14 Harrad (Mayor - 46' ) Substitutes 21 Jensen 04 Hinds 11 Holden 12 Sedgwick 15 Mayor 18 Sinnott 20 Reindorf Southend United 17 Bentley 02 White 03 Coker Dismissed after an earlier booking 05 Phillips 06 Prosser 11 Straker 12 Atkinson Booked 14 Hurst (Timlin - 81' ) 18 Leonard 07 Eastwood (Woodrow - 66' ) 10 Corr Substitutes 01 Smith 23 Thompson 08 Timlin 16 Clifford 21 Payne 09 Reid 33 Woodrow