 Complete the following phrase:  On 23 April 2013, Müller scored two goals and gave an assist in a 40 win against Barcelona in the first leg of the Champions League semi-finals at the Allianz Arena. In the return fixture, Müller scored a header as Bayern won 30 to hand Barcelona their biggest ever aggregate defeat in the Champions League, with a 70 scoreline across the two matches. Müller then went on to play an important role in Bayerns 21 victory over Borussia Dortmund in the 