The Germany star has set his sights on avenging their defeat in the 2012 Champions League final and says his team need to improve defensively under Pep Guardiola
Chelsea won the 2011-12 Champions League final against the Bavarians 4-3 on penalties, but the Germans eventually bounced back by securing the treble the following campaign.
But despite the success, Muller says his team are ready to retaliate for the defeat two seasons ago, when they meet Mourinho's side in Prague at the end of the month.
"We still have a score to settle," the 23-year-old told the club's official website.
"We can't make the lost Champions League final [in 2012] forgotten.
"However, you don't always reach the European Super Cup final, so we will try to win this title with a vengeance."
Muller also took the time to praise the club's new signings Thiago Alcantara, Mario Gotze and Jan Kirchhoff.
"They bring a lot of quality into the team. We don't have to say much about Thiago and Mario. Both have shown what they're capable of at a very high level already.
"But Jan is very talented as well, he will strengthen our defence."
And speaking of the defence, Muller believes that this is the one area his team needs to improve in order to build upon their treble-winning 2012-13 campaign.
"We already have a lot of creativity and different possibilities to score goals going forward.
"Therefore, our main focus is on the defence in the upcoming weeks."
Pep Guardiola's men are currently preparing for the Bavarian derby against Nurnberg on August 24.