Jay Simpson's long-range effort ten minutes from time secures a point for Millwall against out-of-form Brighton.
Brighton have now gone without a league win in six games following their 1-1 draw with Millwall.
The Championship's early pace-setters missed an early penalty when Ryan Harley's tame effort was saved by Millwall's David Forde.
Brighton did take the lead 15 minutes into the second-half when Craig Noone's volley flew into the top of Forde's goal.
However, Jay Simpson equalised for the Lions ten minutes from time, firing home from fully 30 yards past the diving Kasper Ankergren.
The Seagulls drop out of the play-off positions to ninth while Millwall fall into the bottom three.