The Bayern Munich star believes that their Champions League semi-final is not decided just yet, insisting that the Bundesliga champions must replicate their first-leg performance
The Bavarians impressed with a fine performance at the Allianz Arena on April 23 and the Dutchman has stressed that they must put in a similar display at Camp Nou in order to make it to the final.
"We want to make the final, and that means playing just as well as we did in the first leg, not one single per cent less," Robben told Bayern's official website.
"The biggest mistake we could possibly make would be to think we're already through to the final. If there is a team capable of correcting a four-goal deficit, it's Barcelona.
"Maybe we'll have to concentrate even harder than the 100 per cent we managed in the home game, from the first minute onwards.
"We have to be ready for everything, including quick ballboys. Barcelona are well aware that if we score, they need six."
Bayern will qualify for the Champions League final for the third time in four seasons if they eliminate Barcelona.