Brighton left with mountain to climb
Sheffield Wed 2 Brighton 0
Brighton's push for automatic promotion became a distant memory as Sheffield Wednesday grabbed the play-off initiative on a calamitous night for Chris Hughton's side at Hillsborough.
Goals either side of half-time from Ross Wallace and Kieran Lee put the Owls - who finished 15 points adrift of Brighton - in the driving seat ahead of Monday's second leg.
The Seagulls lost four players to injury and had to play the last half-hour with 10 men having used all their substitutes.
Wednesday went ahead in the last minute of the first half when Wallace cut in off the wing and fired home. Lee tucked away a through-ball on 72 minutes.
Former Dundalk star Richie Towell made a belated league debut off the bench for Brighton, coming on at 1-0 but making little impact.