Bayer Leverkusen thrashed 10-man Bochum to notch up a half-century of unbeaten matches in all competitions.
Patrik Schick’s crisp strike put Leverkusen ahead and Victor Boniface increased their lead from the penalty spot.
Amine Adli added a third in the second half with a header from a corner before late goals from Josip Stanisic and Alex Grimaldo completed the rout.
Xabi Alonso’s side are now within one game of completing the first part of an invincible treble.
If Leverkusen avoid defeat in their final league game of the season – at home to Augsburg next Saturday – they will become the first team to through a Bundesliga campaign without tasting defeat.
Bayern lost just once in their title successes of 1986-87 and 2012-13.
After next weekend the Bundesliga champions face Italian side Atalanta in the Europa League final in Dublin on 22 May and play in the German Cup final against Kaiserslautern in Berlin three days later.