Dunfermline manager Jim McIntyre is concerned his side could lose ground following their 4-0 defeat by Hearts.
A draw would have taken the Pars off the foot of the table and McIntyre insists they need to show more fight in their survival bid.
"It's important you don't get detached," said McIntyre. "We had an opportunity coming here to try to move off the bottom of the league and we knew that before the game started.
"But we shot ourselves in the foot."
McIntyre lamented his side's persistent defensive frailties following the loss, describing Hearts' early goal as "deja vu".
"It's very frustrating, but I'm sure it's as frustrating for the players as it is for us on the sidelines," said Mcintyre. "We're all in it together.
"As I've said previously, until we defend properly at set plays then we're going to struggle to win football matches.
"Hearts looked as if they could score at every set play in the first half and that's not good enough. It's lack of concentration and we know that.
"You're assigned a job, it's your responsibility to do it. Until we do that, we're going to struggle."
Ninth-placed Aberdeen are now six points clear of Dunfermline, who are level on points with Hibs and one point behind Inverness and McIntyre is concerned the three sides are losing ground but will work hard to make improvements.
"We'll knuckle down and just keep battling away," he added.
"I believe in this group of players I've got. They're under performing.
"I think we're far better than what we're showing. We need to do the basics better."