Brighton goalkeeper Casper Ankergren says the Seagulls must be at their best to stay at the top of League One.
Albion are on a run of four league games without a win and have had their lead at the top cut to three points.
The 31-year-old told BBC Sussex: "We are not that good that we can play at only 90%.
"I'm not saying we're not trying to put in an effort because every player will try to do their best [but] maybe we haven't been good enough."
He added: "We try to do everything right but things haven't been going for us. When times are tough you need to show some character."
Brighton welcome Notts County to Withdean Stadium on Friday night, and Ankergren is especially keen to keep a clean sheet after conceding seven goals in four games.
"It's vital in this league to keep clean sheets if you want to be promoted," the Dane said. "At the end of the season you need at least 20 to be up there.
"We are more than capable of scoring in every game. I'm happy with winning 1-0 against County - that'll be more than enough for me."
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