Debut duo Sean Thornton and Adam Boyd scored as Leyton Orient started the new season with a win.
Mark Gower converted a Alan McCormack cross to put Southend ahead but Thornton equalised in spectacular style with a 30-yard free kick.
Orient dominated after McCormack was dismissed for a second bookable offence although Wayne Gray and Boyd directed weak shots straight at Darryl Flahavan.
Boyd eventually converted an Efe Echanomi cross with four minutes left.
Southend: Flahavan, Gilbert, Clarke, Barrett, Wilson, Campbell-Ryce, McCormack, Maher, Gower (Black 84), Harrold (MacDonald 90), Hooper (Bailey 61).
Subs Not Used: Collis, Richards.
Sent Off: McCormack (58).
Booked: Maher, McCormack.
Goals: Gower 24.
Leyton Orient: Nelson, Purches, Mkandawire, Saah, Palmer, Melligan (Demetriou 76), Chambers, Thornton, Corden (Daniels 67), Gray (Echanomi 84), Boyd.
Subs Not Used: Morris, Terry.
Goals: Thornton 38, Boyd 86.
Ref: B Knight (Kent).