Albion boss Steve Coppell blamed "naivety" for his injury-hit team's first defeat in five matches at Nottingham Forest last night.
The Seagulls lost 3-2 at the City Ground to stay at the bottom of the division one table.
Albion almost staged another thrilling comeback but a repeat of Saturday's great escape at Preston was just beyound them.
Goals by Marlon Harewood, David Johnson and Jack Lester put Forest 3-0 up with 14 minutes left.
Steve Sidwell scored his second goal in successive games to pull one back with ten minutes remaining and a Nathan Jones' stoppage time screamer ensured an anxious final few minutes for high-flying Forest, but an equaliser was just too much to ask for.
Coppell said: "We rode our luck in the first half. They had some great opportunities but two of their goals came from our set pieces, hitting us on the break, and that is showing our naivety.
"It was again naivety to be 2-0 down at half-time. A lot of their chances were created from our poor distribution from the back.
"You can get away with it against a lot of teams but not one as good as Forest."
Albion were without the injured Bobby Zamora, Graham Barrett and Dean Blackwell.
"Bobby is an exceptional player. If you tried to buy him in the transfer market he would cost an awful lot of money and, unless we can compensate for the occasions he is not there, it is going to be a long season," Coppell said.
"We scored two goals without him so I have got to be pleased with that. It wasn't just Bobby. Graham Barrett has done well for us and then there is Paul Kitson, who I believe is at the club!
"They are three forwards who could really make a difference for us. To compensate for their loss is very hard. You pay money for goals and we haven't got any more money left."
Coppell recalled Charlie Oatway, 29 today, to do a man-marking job on Lester.
He said: "We recognised Jack Lester is the springboard for a lot of their attacking play and I felt Charlie Oatway is more of a hounding personality in the middle of the park but he had his hands full."
Paul Watson will miss the match at Derby on December 14 through suspension after collecting his fifth booking of the season last night.
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