Head coach Oscar Garcia felt skipper Gordon Greer's dismissal in Brighton's 1-1 home draw with fellow play-off contenders Reading "completely changed the game".
Reading are up to sixth in the Sky Bet Championship after a 1-1 draw with fellow play-off hopefuls and 10-man Brighton at the Amex Stadium.
Brighton have injury doubts over Rohan Ince and Andrea Orlandi ahead of Saturday's Sky Bet Championship clash with Reading at the Amex Stadium.
Brighton assistant boss Nathan Jones admits the club face two pivotal home games over the next few days.
Injured Brighton midfielder Andrew Crofts remains on course to be fit for pre-season training.
Brighton striker Will Hoskins has taken another big step along the comeback trail.
Scotland assistant manager Mark McGhee is happy with the growing competition among the nation's strikers.
Brighton assistant manager Nathan Jones acknowledged his Seagulls had got lucky after David Lopez scored a dubious first-half penalty to sink Millwall 1-0 at The Den.