BRIGHTON 2 (Mackail-Smith 15 pen, 47), UNITED 2 (Diouf 36 pen, Brown 65)
Brighton: Kuszczak; Bruno, Greer, El-Abd, Bridge; Bridcutt, Hammond (Crofts 78), Orlandi (Dicker 78); Buckley, Mackail-Smith, Barnes (Dobbie 82). Subs: Ankergren (GK), Dunk, Calderon, Lopez.
United: Kenny, Peltier, Lees (Pugh 41), Pearce, White, Byram, Brown, Austin, Tonge, Diouf (Norris 80), Varney Becchio 65). Subs: Ashdown, Green, Pugh, Gray, Hall.
Referee: Lee Mason
Booked; Buckley, Bridcutt, Crofts (Brighton), Brown, Pugh (Leeds)
Att: 26,402. (2,062 Leeds)
United manager Neil Warnock opted for an unchanged side for the televised clash with Brighton, the boss sticking with the same team that accounted for Southampton in the Capital One Cup in midweek.
And it was United who had the first opportunity of the game when Will Buckley was booked for a foul 30 yards out and Rodolph Austin sent a free-kick wide of the mark.
At the other end, Tom Lees had to block an Ashley Barnes strike into the box after Brighton attacked quickly. Barnes also clipped a shot wide after a great advancing run and ball in from Wayne Bridge.
The hosts felt they had claims for a free-kick on the edge of the box when Craig Mackail-Smith went to ground under pressure from Jason Pearce, but they did have a free-kick moments later when Michael Brown was adjudged to have fouled right on the line. Andrea Orlandi's free-kick was deflected to safety.
But they were handed another chance on 15 minutes when Lee Peltier was adjudged to have tripped Buckley in the box and referee Lee Mason pointed straight to the spot. Mackail-Smith stepped up and smashed the spot-kick straight down the middle of the goal.
There was another great chance for Brighton when Orlandi should have done better following another good move and United were forced to deal with some real pressure during the opening half-hour.
There was a stoppage on the half-hour when Tom Lees appeared to be take a real whack in the face while going up for an aerial challenge on the halfway line, but play was allowed to continue until Brighton's attack broke down before the player received treatment.
United were given a route back in on 35 minutes when Luke Varney went down in the box, following an apparent off the ball incident, and El-Hadji Diouf stepped up to smash home an equalising penalty.
Brighton responded with another Mackail-Smith inspired attack, and Peltier had to be alert to clear the danger. And before half-time, Warnock had to re-arrange his back four with Danny Pugh coming on for the injured Lees, Peltier moving to centre-back.
And it was Leeds who were next on the front foot when Brighton had to clear a Diouf cross. But the hosts went close again before the break when Mackail-Smith hit a first time shot just wide of the mark.
But Mackail-Smith made no mistake two minutes into the second half when he finished off some neat passing play, following a throw-in, by driving home an angled effort.
Moments later, Bruno Saltor sent a free-kick fizzing over the bar after Brown was adjudged to have fouled on the edge of the box. The home side were playing some good stuff, and Pearce had to make one important clearance when they threatened again.
United responded with Aidy White having a shot deflected wide after a surging run forward. And it was all square moments later when Brown struck a first time shot from the edge of the box which left Tomasz Kuszczak with no chance.
And substitute Luciano Becchio came within a whisker of giving United the lead when he glanced a header wide after a great ball in from White.
But with 17 minutes left, the pendelum appeared to swing again when Mackail-Smith went down under pressure from Sam Byram for the third penalty of the night. This time Kenny was equal to the spot-kick and made a great save down to his right.
Byram next threatened at the other end when he forced Kuszczak into making a good save after an advancing run.
As the game entered its closing stages, Mackail-Smith was pulled up for handling at a crucial moment and Stephen Dobbie sent a shot over the top of Kenny's bar.
Five minutes were added to the 90, and United went close in the third of those when Michael Tonge sent a free-kick just wide after Brown won a free-kick on the edge of the box.
There was still time for Kenny to make one last contribution, when he made a great save to claw away an Andrew Crofts effort.