Petr Cech has delivered a damning assessment of Chelsea\'s current failings, pinning the blame firmly on the players and absolving manager Andre Villas-Boas of responsibility. Goalkeeper Cech accused his team-mates of failing to defend aggressively enough during their current slump, of repeating the same mistakes over and over again, and of being persistently wasteful in front of goal, before demanding that last night\'s defeat at Bayer Leverkusen should herald the end of their malaise. The 2-1 UEFA Champions League loss marked a new low in what has been Chelsea\'s worst start to a season since Roman Abramovich bought the club, piling the pressure on Villas-Boas. Having crashed out of the Premier League top four, the Blues are now in real danger of failing to reach the knockout phase of Europe\'s premier club competition, something unprecedented in the Abramovich era. The billionaire Russian\'s patience with his new manager would be tested to the limit were Chelsea not to qualify for the last 16 but Cech insisted any wrath should be directed at his multi-million-pound squad, who are repeating the slump that cost Carlo Ancelotti his job last season. He told the club\'s official website, www.chelseafc.com: \"The manager is not on the pitch, we are on the pitch and we are making mistakes. He cannot do anything about individual mistakes while he is standing by the bench. So the players are to blame and we know it and we try to make things happen and change. It is not easy but we keep going.\" He added: \"We have been talking recently about the same mistakes - concentration and little details when we don\'t go to clear the ball. I think we need to be much more aggressive in terms of defending. \"There are no excuses. We need to look first at ourselves and then we can criticise the other people because we put ourselves in the situation where we were 1-0 up and we could have killed the game off. Then there would be no discussion whatsoever about things that were happening in the game. We have to take it like that and make sure that this is the last time it happens.\" Chelsea now need to beat Valencia or keep a clean sheet in their final Group E game to avoid being dragged into the UEFA Europa League. Cech said: \"We have put ourselves in a difficult situation because we could have had qualification done a month ago but that is the way it is. We are one of the top teams in Europe and this is not a situation we want to be in. The reaction of the players is that we can show on the pitch that we really mean what we say.\" While Chelsea skulked from the field at the BayArena, Leverkusen celebrated wildly with the home supporters after sealing their own qualification from Group E. Star midfielder Michael Ballack rubbed salt into his former club\'s wounds by declaring he knew the visitors were there for the taking, even when they led 1-0. \"You could feel it on the pitch,\" he said. \"Every minute, especially at the beginning of the match, they were not that strong as they normally are. Even when they were 1-0 ahead, they were not that safe or had the confidence they normally have and we felt this on the pitch.\" Despite being jettisoned by Chelsea 18 months ago, Ballack took no pleasure in their or Villas-Boas\' plight. \"I\'m not as happy as I normally am when you get to the next round,\" said the 35-year-old, who played under four different managers in his four years at Stamford Bridge. \"I played four years for Chelsea and I know how quickly it can go (wrong). I had a few managers in this time. I know it\'s always difficult for the coach. He\'s young, ambitious and is a good guy. He had success with his last team and at the moment it is not easy for everybody. But it is not just the coach, it is also the players. They have to get out of the situation all together.\"