A disappointed Chris Hughton admitted his side were not at the level they need to be in the Premier League after their 2-0 defeat to Leicester City.
The visitors trailed after just 52 seconds to a tap-in from Shinji Okazaki after a Mathew Ryan mistake and added a second through Harry Maguire in the second half for their comfortable victory.
It was a sloppy display from the Seagulls in what was their first top flight away game for 34 years and Hughton was left to rue two 'soft goals' and a 'big disappointment'.
He said: "It was always going to be tough, but I am disappointed with the performance today. This won't be the first time this season, we will have many of these this season. It is about staying in there, perhaps not playing so well and having the opportunity to stay in the game.
"What this group of players cannot afford to do is get their heads down as every game we play is an opportunity to get something.
"The way to sum it up is we came away from a performance against Manchester City which I thought overall there were enough good parts of our game I could pull out, but when you come here away from home, the last thing you need or want to do is going 1-0 down so early in the game.
"From our attack, that's a big disappointment for me. It always becomes a little bit of an uphill battle, we certainly weren't at the level we needed to be on the ball, but we stuck in there.
"At 1-0 you have still got a chance, but then it's difficult again when we conceded again, particularly at a set-play where we have to be better. It's then very, very difficult to get a result.
"It's two soft goals, we are up against a team here, who have had great league experience in the three years they have been here and what they achieved the season before.
"I felt there was an opportunity for us to play better and get some sort of input in the game. In a game where we do have a bit more input than we did, then we have a chance of getting back into it.
"We have not really made their keeper work, we had little periods when we got into good areas. Into wide areas and not as many as them, but not far off if I am talking about good crossing positions, but we never made the most of them."
Hughton could not elaborate on the injury suffered to Glenn Murray which forced his second-half withdrawal, but confirmed it was from an early tackle and the striker himself felt he could not continue.
On a potential penalty in the first half where Jamie Murphy's effort struck Wes Morgan's arm, Hughton added: "I must admit I haven't seen it again, but my gut feeling was his arms were fairly close to his body. I didn't think it was at the time."