Bayern Munich lost 2-1 at promoted Mainz to remain without a victory in the German Bundesliga under new coach Louis van Gaal.
|Mainz players celebrate after playing giant killers [GALLO/GETTY]
Andreas Ivanschitz and Aristide Bance scored for Mainz, which had never before beaten Bayern in previous seasons in the Bundesliga.
Bayern, the German powerhouse, has two draws and loss to be in 12th place.
Bayer Leverkusen thrashed promoted Freiburg 5-0 on the road and moved past Schalke to top the standings.
Defending champion Wolfsburg could emerge as the sole leader if it beats Hamburger SV on Sunday.
In other games, Borussia Dortmund and Stuttgart drew 1-1, Hannover won 2-0 at FC Nuremberg under an interim coach and 10-man Eintracht Frankfurt held on for a 0-0 draw at FC Cologne.
In Mainz, the home team came out roaring and put Bayern immediately under pressure.
Ivanschitz found the target in the 25th, shooting with his left foot from the edge of the box. Bayern goalkeeper Michael Rensing dived to his right but the ball bounced over his arm into the net.
Bance scored in the 37th after he had earlier hit the crossbar with an overhead kick and then sent a header over the top.
With its defence in disarray, Bayern failed to clear a cross from Florian Heller and and Bance headed past Rensing.
Van Gaal replaced Hamit Altintop and Danijel Pranjic with Thomas Mueller and Ivica Olic before halftime, and Bayern played better in the second half and got back into the match when Mainz's Nikolce Noveski headed into his own net in the 47th.
Without playmaker Franck Ribery, who is still not fully fit after knee tendinitis, Bayern couldn't break through again.
Stajner secures win
In Nuremberg, Jiri Stajner scored the first goal for Hannover, then earned a penalty and converted it himself.
However, the referee ruled that the spot kick had to be retaken. Stajner chose the same side and goalkeeper Raphael Schaefer saved the attempt.
The Czech midfielder redeemed himself by securing Hannover's victory in the 86th.
Hannover and coach Dieter Hecking parted company earlier this week and Andreas Bergmann got the team's first win of the season as the interim coach.
Tranquillo Barnetta and Eren Derdiyok each scored two goals, and Stefan Kiessling added one for Leverkusen to rout promoted Nuremberg.
Cologne could not beat Eintracht even after Patrick Ochs was sent off in the 55th minute and remains winless.
Stuttgart rallied to earn the draw in Dortmund. Nelson Valdez had put Dortmund ahead in the 27th and defender Georg Niedermeier headed in the equaliser two minutes into the second half.
Schalke and Hoffenheim drew 0-0 on Friday.