Barcelona midfielder Andres Iniesta has admitted that the Catalan outfit cannot afford to "slip up" in Wednesday's Champions League quarter-final second leg against Atletico Madrid.

The two sides are level at 1-1 from the first leg last week, with Neymar's late strike cancelling out a long-range Diego effort for the visitors.

"It would be nice to play a great game and reach the semi-finals, which is where we want to be," he told Mundo Deportivo.

"It was an intense game, both physically and mentally, and there was a lot of pressure [from Atletico in the first leg]. We will fight for it knowing it will be very intense from the first minute to the last.

"We have played Atletico four times this season and drawn against them on all four occasions. The conclusion is we are evenly matched. Atletico require you to be very focused and not slip up."

Each of the four matches between Barcelona and Atletico this season have ended in draws.