The forward scored in Munich's 5-0 trouncing of Fortuna Dusseldorf yesterday that meant the Bavarian club are the first in Bundesliga to history to win all eight of their opening games.
"There are more teams than just Borussia Dortmund," Muller, 23, told Sky.
"We can be pleased that we have made such a good start to the season and we have learnt to concentrate only on ourselves.
"If we carry on playing like this, then it will be hard for any opponents to beat us."
Next up for last season's beaten European finalists is a trip to Lille in the Champions League on Tuesday.