Reigning German champions Bayern Munich only needed to win away to FSV Mainz on Saturday to secure their ninth straight Bundesliga crown.
However, the Bavarians battled against the in-form midtable side who scored goals from Jonathan Burkardt and Robin Quaison.
Robert Lewandowski, playing in his first game back from injury, pulled one back in stoppage-time but it was too little too late.
“It’s a pity we couldn’t make that step today,” Bayern boss Hansi Flick said.
“Mainz did very well, defended aggressively and kept it tight. We hardly had a chance to score, they defended their goal outstandingly.
“In the first half, we weren’t playing the way we wanted. In the second half it was better. But we couldn’t break through.”
Second-placed RB Leipzig can close the gap on Bayern to seven points when they host Stuttgart on Sunday. However a Leipzig loss would confirm Bayern’s title triumph.
If not, Bayern’s next chance to seal the title will be at home against Borussia Moenchengladbach next Saturday.
“We have to put this game behind us,” Flick said.
“The players have a lot of minutes and games in their legs. Today it didn’t look like we knew what we were doing on the pitch.
“It looked a little slower, we didn’t act with the same intensity we normally do. We have three games left and we need one win. I expect us to get that.”