Frank Lampard has warned Barcelona that there is unfinished business from their 2009 Champions League semi-final encounter.
The Blues were beaten by Pep Guardiola's men in controversial circumstances, with referee Tom Henning Ovrebo being blamed for a poor display.
Didier Drogba labelled the Norwegian a cheat after he failed to award Chelsea what he felt were two blatant penalties.
Lampard believes that the players who remain from that night will need no firing up when the teams meet in this year's semi-final.
"Everyone's got unfinished business with them," said Lampard. "You have to respect that they are the greatest team in the world. They have been and still are at this present time.
"That game is still in our minds obviously but this is a completely different year so we need to try to beat them this year."
The other semi-final pits Read Madrid against Bayern Munich.
Germany
Switzerland
Hungary
Scotland
Spain
Italy
Croatia
Albania
England
Denmark
Slovenia
Serbia
Austria
France
Netherlands
Poland
Romania
Belgium
Slovakia
Ukraine
Portugal
Turkey
Georgia
Czech Republic