Leaders Bayer Leverkusen defeated 10-man Union Berlin 1-0 on Saturday and could claim their first-ever Bundesliga title next weekend at home against Werder Bremen.
Florian Wirtz scored the winner shortly before the break to give Leverkusen a 16-point advantage over second-placed Bayern, who were up 2-0 but conceded a shocking 3-2 defeat to promoted Heindeinhem.
Leverkusen, who are unbeaten in all their 41 season matches and a record-equalling 28 in the Bundesliga in 2023-24, can end the title race with a home win against Bremen next Sunday, no matter the result of Bayern Munich v Cologne on Saturday.
If Bayern lose to Cologne, Leverkusen will be crowned champions before their own game.
Leverkusen have been in the Bundesliga since 1979, and won the UEFA Cup in 1998 and German Cup in 1993. But they have not lifted a trophy since then, with several near misses including three lost Cup finals and five Bundesliga runner-up finishes - which earned them the nickname Vizekusen (Vicekusen) in Germany and Neverkusen abroad.
Elsewhere, RB Leipzig thrashed Freiburg 4-1, Mainz defeated Darmstadt 4-0 and Cologne scored two goals in stoppage time to claim a 2-1 comeback win against Bochum.
