The naked man came off second best after he evaded security and charged towards Symonds while he was batting during Australia's run-chase.
Symonds stood his ground as the man approach and dropped the pitch invader with a rugby-style shoulder charge.
The man was arrested by police and faces the possibility of a fine and a life ban from the Gabba.
Symonds also faces the risk of punishment under the International Cricket Council's strict code of conduct.
The code includes a section banning players from any physical assault of a rival player, official or spectator.