Coach Carlo Ancelotti has warned his side to concentrate for the full 90 minutes as Chelsea look to seal top spot in Group D with victory over Porto on Wednesday.
The Blues conceded a last minute goal against Atletico Madrid in their last Champions League outing after leading 2-1 with eight minutes remaining.
Chelsea target Sergio Aguero scored the equaliser with a stunning free-kick to make Ancelotti's side pay for some sloppy defending in the closing seconds.
Ancelotti knows that victory over Porto will not be easy. They only just managed to overcome the Portuguese side 1-0 at Stamford Bridge thanks to a goal from Nicolas Anelka.
A win would ensure that Chelsea qualified in the all-important first place in the group but Ancelotti maintains they must learn from previous mistakes in order to finish top.
"In Madrid we showed a very good mental attitude at the end of the game to keep attacking and scoring goals," said Ancelotti.
"It was disappointing to concede two goals to Atletico, especially one in the last minute, but we will learn from this to keep our concentration until the end.
"Even with a draw against Atletico we qualified from our group in the Champions league but we still want to come top and we will all be working hard in the last two games."
