With nine games of the season remaining, just three more wins are required to seal the title, but they could win it ever sooner if other results go their way.
"There is no question that we are going to win the title this year, we just have to see when that will happen," said midfielder Toni Kroos.
Only coach Jupp Heynckes was remaining cautious.
"Until it is mathematically certain, we will not be taking congratulations from anybody," he said.
However, he was quick to pass on the compliments to opponents Fortuna, who went close to inflicting only his side's second defeat of the season.
Bayern twice trailed in the match and needed a late winner from defender Jerome Boateng to snatch all three points.
"It was very tight and I've got to pay compliments to Fortuna," the coach said. "They made life difficult for us.
"This game showed that no game is won before the kick-off.
"But we saw that we have such a fantastic morale that we were able to win the game with our substitutes. We turned it around with our class."