Sean Dyche admits his players have to tighten up at the back, after Sunday’s 4-2 defeat to Fulham at Craven Cottage.
Burnley only conceded 39 goals in 38 Premier League games last term on the way to finishing seventh – and they shipped seven in their last two once Europa League football was assured.
However, they have given up seven in their last two league games, after a goal-less draw at Southampton, and Olympiakos put three past them on Thursday night.
Dyche said: “We gave away some sloppy goals. I don’t want that to continue, because we did it against Watford and again (at Fulham). Olympiakos was different, we changed the team and all that stuff.
“But that back four (at Fulham) have been pretty settled. It’s not just the back four, the whole team are culpable in the end, but you always look to your back four and how they’re operating.
"Not a million miles away, but, the margins are really tight in this division and we’ve got to correct that.
"But from our point of view, I know we can do better because I’ve seen us do better, with our organisation, and also our detailing in our defending.
“So we need to correct that and find that again.”