Bayern Munich crashed 3-1 at mid-table Mainz a week after clinching a 10th straight Bundesliga title on Saturday.
Second-placed Borussia Dortmund also lost 3-4 at home against Bochum in spite of an Erling Haaland hat-trick.
Mainz won from Jonathan Burkardt’s low drive, Moussa Niakhate’s tap-in and Leandro Barreiro against a make-shift Bayern side.
Robert Lewandowski was on target for his 34th league goal of the season and record 18th away goal in a Bundesliga campaign.
Haaland reversed a 2-0 deficit from Sebastian Polter’s header and Gerrit Holtmann’s classy shot into the far right corner with two first-half penalty kicks and a fumbled effort.
But Bochum had the last laugh from Jürgen Locadia and Milos Pantovic’s penalty kick in the final minutes.
Bochum’s first win in Dortmund in 24 years made sure that they would not be relegated.
The day’s drama was at the bottom where VfB Stuttgart and Arminia Bielefeld got last-gasp 1-1 equalisers against Wolfsburg and Hertha Berlin respectively in their fight against the drop.
Substitute Chris Führich volleyed into the roof of the net in the 89th minute for third-last Stuttgart to cancel out John Anthony Brooks’ early header for Wolfsburg, who are now safe.
In Bielefeld, Hertha Berlin led from Lucas Tousart’s goal, but Joakim Nilsson headed the hosts level in stoppage time to mean that Hertha are not yet safe.
They are four points ahead of Stuttgart in the relegation play-off spot with two games left, with second-bottom Bielefeld another two back.
“We weren’t brilliant but we weren’t expecting this. Unfortunately, we came under pressure in the end. The situation remains critical between Stuttgart and us,” Hertha coach Felix Magath said.
Magath added he hopes that Bayern Munich will make a bigger effort next weekend against Stuttgart than they did on the day in Mainz.
A Bayern Munich win will assure Hertha Berlin of survival, regardless of the outcome of their game against Mainz.
European contenders Cologne won 4-1 in Augsburg, thanks to teenager Jan Thielmann, Mark Uth and a second-half brace from Anthony Modesto.
The hosts are all but safe in spite of the heavy defeat.
Cologne rose into sixth place past Union Berlin, who drew 1-1 with relegated Greuther Fürth on Friday.
The remaing three games for the match day are Hoffenheim vs Freiburg later on Saturday and Bayer Leverkusen vs Eintracht Frankfurt, and Borussia Mönchengladbach vs RB Leipzig on Monday.
But they are also important in the fight for European berths.
