lackburn manager Sam Allardyce admits his side have to rediscover their defensive stability if they are to escape from their current malaise.[LNB] Last night's Carling Cup defeat at Aston Villa, where they led 1-0 but conceded three second-half goals - two in very quick succession - highlighted a familiar problem this campaign.[LNB]In three of the four Premier League matches since beating Everton on the opening day of the season - their only victory so far - Rovers have taken a lead but failed to close out the game.[LNB]That is most unlike Allardyce's side and he knows it has to change.[LNB]"It is the clean sheet mentality," he said.[LNB]"The reason we were so successful last season was that we had 13 clean sheets in a very difficult season where the transformation of the team was massive.[LNB]"We know each other a lot better than we did then and we should be more experienced in terms of the know-how we should have but unfortunately we are not finding that to be the case.[LNB]"We looked all right against Everton, when it looked like it was all clicking into place, but then we went to Birmingham (losing 2-1).[LNB]"It starts to knock the confidence a bit when performances are good and results don't follow.[LNB]"We are not too bad but we should have notched up at least another win in the Premier League and we have got to make sure we get a win shortly.[LNB]"That heaps the pressure on winning the next two games away because winning away for us is much more difficult than winning at home.[LNB]"We have got to do it somewhere in the next two games, either at Blackpool on Saturday or Stoke."[LNB]Having seen his side pegged back by Fulham last weekend, Allardyce then had to watch as Villa staged a comeback to knock them out of the cup.[LNB]"It's been a pretty miserable week, especially after the Aston Villa scenario because I didn't see what was coming," admitted the Rovers boss.[LNB]"Normally you can see the opposition building up pressure but it went AWOL all of a sudden and that was disappointing considering the level we were playing at again.[LNB]"The first goal was something we should have done better with but two goals in the space of a minute or so was the real killer.[LNB]"That left me very disappointed last night but I don't think the Villa result has a huge bearing on the Premier League.[LNB]"But it would have been nice to win a game of football - which we haven't done since Norwich in the last round.[LNB]"It would have given us a great boost, had we won it, going into the weekend."[LNB]Defender Phil Jones, who has been employed in midfield this season, accepted the team had to tighten up after throwing away so many points already.[LNB]"We've been leading too many times this season and given games away when we should have won," Jones said.[LNB]"It is something we have definitely got to improve on and improve on it quickly.[LNB]"It is an absolutely massive game against Blackpool, we have to win and we know we have to, but we respond well to pressure."