Dutch winger believes they face the 'most dangerous side left in the competition.'
Despite winning the Champions League last year Bayern Munich are playing down any perceived superiority over Real Madrid as they travel to the Bernabeu.
Arjen Robben and his teammates are well aware of the threat posed by Carlo Ancelotti's men in tonight's semi-final first-leg.
And he says there can be the potential for an upset.
'We are no longer favourites,' said the 30-year-old. 'Of course we want to win the Champions League again, but we're in the semi-final and anything can happen.
'[Real] have the best players. If you have a ten minute period where you switch off, you can suddenly concede three goals. There'll be a lot demanded of us.'
While the former Chelsea player is right to be cautious about how Munich approach their visit to Madrid, he is ever so slightly overstating the point.
Perhaps he wants to avoid complacency or perhaps he is even playing 'mind games' to heap pressure on Los Blancos.
Whatever it is this game should be recognised as a fairly even matched affair, whichever way you look at it.
Bayern are the holders and with Pep Guardiola in charge, no one can seriously take the notion of them as underdogs seriously, whoever they face.
Although Real possess plenty of 'big game players' they have not won the Champions League for more than a decade.
Moreover Cristiano Ronaldo and his fellow cohorts have to travel away from home for the return-leg which already puts Bayern in a stronger position since they will fancy their chances of progressing to the final backed by their support.
Whatever the outcome this tie will no doubt prove to be a titanic match-up between two of European football's giants. Expect fireworks!