Chelsea coach Avram Grant admitted it was not one of Chelsea's best performances under his tenure but he remained satisfied with a point against Schalke in Gelsenkirchen.
But Chelsea rode their luck to claim a vital point which kept them top of Group B.
Schalke twice hit the woodwork in the second half while Chelsea's Didier Drogba wasted a hat-trick of chances in a goalless draw.
Had Chelsea come away with all three points, then they would have qualified for the next phase following Rosenborg's victory over Valencia in Spain.
But Grant declared: 'We wanted to win but it was not easy to play Schalke at home. They needed to win because a draw was not good enough. It was not a bad result but not our best game.
'After so many good games in a short time we can have one game that is not in the high level. It is also an away game against a team who feel very good playing at home.'
One blight for Grant was a first half injury to goalkeeper Petr Cech. The Czech international could not return for the second half but Grant could not say how long Cech would be sidelined for.
Grant added: 'He could not continue in the second half. How bad the injury is we need to wait and see. It is calf injury and I asked the doctor if he could continue and he couldn't. But Carlo Cudicini came on and played well.'
Now Grant is confident that his side can finish the job of reaching the next phase by winning one of their remaining two games against Rosenborg away and Valencia at home.
Grant added: 'The Champions League is not the league it is another competition. You need to fight for the result and it is not easy to play away from home.
'We are in first place and everything is in our hands and I am very happy and confident about that. But we need to continue our job because it will not be easy.
'I don't think we defended so bad. It was not a bad game. It was not our best performance but not a bad game for us.'
Schalke coach Mirko Slomka was happy with his team's performance and knew better finishing could have earned them a renowned victory.
Slomka said: 'We showed a lot of passion and stuck to our tactical instructions.
'We knew how dangerous Chelsea could be. But we had lots of chances and were well organised. I have to praise my players.
'We tried to learn from the first game in London where we had problems with their full-backs getting forward.
'But tonight our full-backs were the ones going forward. I think Chelsea didn't defend as well as they should have done because we were so good going forward.'