Petr Cech has refused to criticise his team-mates for Chelsea's recent lack of clean sheets, despite giving them a dressing down last season.[LNB] Blues goalkeeper Cech, who once went a record 1,025 minutes without conceding a Premier League goal, has not enjoyed a top-flight shutout since the opening day of the current campaign.[LNB]But the 29-year-old was confident the clean sheets would soon return, claiming the current run was more down to bad luck than bad defending.[LNB]That was in stark contrast to his attitude in March, where he berated his team-mates for the late goal they conceded in their 3-1 victory at Blackpool.[LNB]"You can see everybody's concentrating and focused on their jobs," Cech said.[LNB]"When you concede sometimes, you have to accept that the opponent had a very good chance to score.[LNB]"Against Blackpool last year, it was because, at 3-0, everybody just stopped doing what they should and that was why I got angry.[LNB]"But that was not the case this season."[LNB]He added: "It's always better when you finish off the games with a clean sheet.[LNB]"We had a little unfortunate run without having a clean sheet but we've played well, we keep winning three points, which is the main target.[LNB]"If you finish the game 0-0, you might be happy with a clean sheet but it's only one point.[LNB]"If you win 3-1, you've got three points and it's more important for the team.[LNB]"We are improving all the time and I think that we will get back to our track of getting clean sheets."[LNB]Chelsea's run has coincided with the summer appointment of Andre Villas-Boas, who has brought a more attacking style of football to Stamford Bridge.[LNB]Cech said: "We are the team who want to control the game, who want to play well with the ball.[LNB]"We are not waiting for the game to finish. We want to kill the game off and maybe this is the reason maybe why sometimes at the end of the games, when you want to score more goals, something like this happens.[LNB]"We were a little bit unlucky as well with the little details. We didn't control the little details. That's why we got punished all the time.[LNB]"We are aware of it and we are improving and it's just a moment where it's happening, but I think it's going to stop."[LNB]Chelsea will never have a better chance to end that sequence than Wednesday night's Champions League game against Genk, the first of a Group E double-header with the Belgian champions.[LNB]Maximum points will be expected from both games, which would all but guarantee a place in the knockout phase.[LNB]Cech boldly declared: "With two victories, we will qualify for the next round."