An Arjen Robben hat-trick and goals from David Alaba and Mario Mandzukic saw Pep Guardiola's men romp to yet another impressive victory at the Allianz Arena.
The result means that the Bavarians now have a 20-point lead with only 11 games remaining and Muller therefore believes that a second successive Bundesliga is already in the bag.
"Realistically, the title race is already over," the 24-year-old attacking midfielder told Munich's TZ newspaper.
"I don't think anybody really expects us to lose [enough of the remaining fixtures], particularly considering we have not lost any of the 23 beforehand."
Bayern, who are now unbeaten in 48 league games, are also on course to defend the DFB-Pokal, having already set up a semi-final showdown with Kaiserslauten in April, and are currently well positioned to progress to the last eight of the Champions League on the back of a 2-0 first-leg win over Arsenal at the Emirates last week.