The German Bundesliga outfit take a 2-1 lead into the second leg, thanks to a late goal from Mario Gomez in Bavaria. However, Lizarazu insists that the club must not count on escaping the Spanish capital with a clean sheet.
"Munich will need a goal in Madrid," he told Kicker.
"Bayern have to be ready for a big fight and a fantastic defensive performance.
"International matches at this level are more mental than anything else, so they have to push the intensity to the maximum."
Meanwhile, the Bavarians travel to Werder Breman in league action this weekend.