Cesc Fàbregas knows FC Barcelona will have to be at their best in Wednesday's UEFA Champions League quarter-final second leg at Club Atlético de Madrid, but believes his team have "many things left to do this season".

Having drawn 1-1 in last week's home first leg, Barcelona need to score at the Estadio Vicente Calderón, and Fàbregas recognises that will be no easy task against opponents they have not beaten in four attempts this term. "We know we will have to see a great Barça in order for us to reach the semi-finals," the Spain midfielder said. "They have a small advantage in the tie. We will have to be brave and not think that this could be a disaster.

"We've played four tough games against Atlético this season," added the 26-year-old, whose side are bidding to get to a seventh successive semi-final. "It will be a very even encounter but we are very hopeful of winning. Atlético will keep it tight. They are not under pressure to attack. It will be difficult. They have their own style but we must try to break them down using our strengths."

The Atlético game plan might change depending on the availability of their talismanic striker Diego Costa, who limped off with a hamstring injury early in the first instalment, although Fàbregas refuses to be drawn on whether the Spanish international's potential absence would benefit Barcelona. "That's a bit of a trick question. [What] if I say I prefer Diego Costa doesn't play – and his replacement scores?

"Diego Costa is a very important player but Atlético have many great players. We have to focus on ourselves. We want to compete and fight until the end. That is how we think. There are many things left to do this season."