Dean Wilkins felt Albion's performance in the first half was to blame for the defeat at Roots Hall.
He said, "The first half has cost us, and their opening goal came from probably our best passage of play. They caught us on the break and with couple of mistakes along the way, before you know it, it is in the back of the net, and that has made it difficult for us.
"The second goal was a bit of a worldy from their centre-half and from then on it was very difficult.
"I'm obviously disappointed with the way that we have performed because I think that in the situation that we are in we should be playing with a little more belief than it looked like we were playing with - in the first half in particular."
The result leaves Albion four points behind Leeds in sixth place, who also have a game in hand. But despite the uphill struggle, Wilkins still believes there is an outside chance the Seagulls could make it into the playoffs.
"It is not mathematically impossible for us to win our last four games and still make the playoffs. When we entered this run of six games we said that we felt we would need four wins and possibly a draw, and we are still capable of getting the four wins.
"The season is still alive for us and we can't possibly give up the ghost now. We have to fight until the very end."
