Bayern won their weekend league fixture against Werder Bremen and fielded a side that had eight different players from the ones that featured in their first leg win over Real last week. Coach Jupp Heynckes knew it was important to rotate the squad as they are now preparing for their 13th game in six weeks.
Muller played in the game against Bremen and he knows that Real are full of confidence having won the Clasico against Barcelona on Sunday. Bayern, for their part, could not prevent Dortmuund from retaining the Bundesliga title and the Champions League remains their last hope of achieving any silverware this season.
But the Germany international is confident that his side will not stumble under pressure and they will ensure that they will progress and take part in a home final.
"We go to Madrid full of confidence," Müller told the club website.
"We know what we're capable of. But we also know we'll have to invest a huge amount if we're to stand our ground there."
His coach echoed his words as he said:"It will be a difficult task, but despite that, my team showed in the first match that we're on a par with them.
"We go there full of belief. I'm optimistic, and so are my players."
Last week, there were reports of a disagreement between club stars Franck Ribery and Arjen Robben. But Heynckes pointed out how the two combined well during their Bundesliga game as evidence that there is nothing wrong with Bayern's team spirit.
The Frenchman scored a last-minute winner over the weekend and Robben congratulated him for the effort as well.
"That scene speaks for itself," said Heynckes. "It was an important, morale-boosting win."
Bayern will play Real on Wednesday and they will find out which side they could potentially face in the final after Chelsea visit the Camp Nou and take on Barcelona on Tuesday.