Centre-back Zat Knight admits Aston Villa's defending in recent games has "not been good enough" after conceding a spate of soft goals.
Villa's slide out of contention for a Champions League spot has coincided with some sloppy defending which has seen them go 10 games without keeping a clean sheet during which period they have conceded 24 goals.
Injuries have deprived Villa boss Martin O'Neill of skipper and central defender Martin Laursen and left-back Wilfred Bouma for lengthy periods.
But Knight is refusing to look for excuses and is aware of the necessity to address the problems in the final six games of the campaign.
The former Fulham player, restored to the side in the absence of back injury victim Carlos Cuellar, told PA Sport: "It's frustrating what has been happening - especially as a defender.
"Your main aim as a defender is to go out there and keep a clean sheet and, we fail to score at the other end, that's not our problem. Our problem is the back.
"It is frustrating and it's just not good enough is it? Yes, we haven't had a settled back four, but everyone's played together before so I think that's just an excuse."
Knight added: "I don't know what the problem is. If I knew what it was, I'd be the manager wouldn't I?
"There are some very soft goals that we have let in. There have been times times when we have been dropping off too deep and teams are getting a run at us. But we've got six games to put it right and we'll just have to sort it out for ourselves."
It was a familiar story during Sunday's 3-3 draw with Everton as Villa were caught napping at the back before fighting back from 3-1 down to salvage a point.
Knight said: "From a fan's point of view, the Everton game was great to watch. But, from our point of view, it was disappointing to score three goals and to concede three goals.
"We're expecting, if we are going to score three goals, to win the game, but it wasn't to be. First half, defensively, we weren't at the races.
"Second half we showed that we can be a lot better. We need to start the way we did second half. But to bounce back like we did shows there's still a bit of fire in us and still a bit of belief.
"Going forward I thought we were excellent, but we spoiled it in the first half with the two goals we conceded."