The German's head to the Bernabeu looking to defend a 2-1 lead that they achieved in the opening leg last week.
Despite acknowledging the attacking threat that Real possess, Heynckes has tipped his side to cause their hosts some problems up the other end.
"The opening-leg result is a little advantage for us," he told reporters. "But Real have shown this season that they can score a scary amount of goals.
"But we have a good balance between defence and offence, so you can prepare yourselves for a treat of football. This will be a battle of giants."
Tomorrow's match will be the 14th time that the two clubs have faced each other in the Champions League.