Striker Eric Maxim Choupo-Moting scored twice on Sunday as struggling Nuremberg inflicted a shock 3-2 defeat on Bayer Leverkusen, their first of the season, to dent their title aspirations.
With league leaders Bayern Munich drawing 1-1 at Cologne on Saturday, the defeat leaves Leverkusen three points off the pace in third, while Nuremberg escape the bottom three after surviving a desperate fightback.
Nuremberg's win raises them up to 15th, which is bad news for bottom side Hertha Berlin, Nuremberg's opponents next weekend in the capital, who are now six points adrift from safety and five points behind second-from-bottom Freiburg.
"I am overjoyed," said Nuremberg's Choupo-Moting, who is on loan from Hamburg. "I knew they had very good defenders, but I was 100 percent determined to put the ball in the back of the net. It was an important win, but every game is important for us from now on. They were special opponents, but so are Hertha Berlin next week."
Nuremberg's win was thoroughly deserved as the hosts enjoyed a 3-0 lead with less than 30 minutes left before Leverkusen fought back. "That was a great performance from my team," said Nuremberg coach Dieter Hecking. "We couldn't do any more after going 3-0 up, but my team fought unbelievably."
Choupo-Moting, 20, showed cool finishing to slot home past Germany goalkeeper Rene Adler on 42 minutes and then held off two defenders to add a second on the stroke of half-time to make it 2-0 at the break.
With the former league leaders stunned, Senegal midfielder Mickael Tavares then added a third on 55 minutes as Leverkusen were staring down the barrel of their first defeat of the season.
Leverkusen finally came to life on 66 minutes when midfielder Arturo Vidal and defender Gonzalo Castro combined to find Stefan Kiessling free in the penalty area and the Germany striker made no mistake with his shot.
And fellow national team-mate Patrick Helmes, making only his sixth appearance of the season after a knee injury, scored the second on 73 minutes to ensure a tense last few minutes.
Both Castro and Vidal were booked in the final moments of the game in their desperation to win the ball back from Nuremberg, but the hosts hung on. "We woke up too late," said Bayer playmaker Toni Kroos. "We weren't aggressive enough in the first-half and didn't win the individual battles. Nuremberg turned their half chances into goals, we were stupid to conceed them."
Burkino Faso striker Aristide Bance hit the winner for mid-table Mainz on Sunday night as they won 1-0 at Hoffeheim.
On Saturday, Germany midfielder Bastian Schweinsteiger saved Bayern Munich's blushes with a second-half equaliser on Saturday as the Bundesliga leaders were held 1-1 at Cologne.
After Lukas Podolski scored against his old club, Bayern were heading for their first defeat in any competition since last November until Schweinsteiger netted to keep Munich two points clear at the top of the table.
Dortmund strengthened their European ambitions by beating Borussia Moenchengladbach 3-0 at home to go fifth in the table. Dortmund's Egyptian striker Mohamed Zidan, who scored against England last week, netted twice.
Second-placed Schalke 04 kept up the pressure on Bayern with an impressive 4-1 win at Eintracht Frankfurt. Hanover, who are just above the relegation zone, picked up their first win in 14 games when they managed a 2-1 win at Freiburg.
Werder Bremen fought back from being 2-0 down to claim a 2-2 draw with Stuttgart to claim the point which leaves Bremen sixth and Stuttgart seventh in the table. Wolfsburg survived an early scare at home to Bochum before recording a comfortable 4-1 win. Hertha Berlin remain rooted to the bottom of the table after their 1-0 loss at Hamburg with ex-Germany defender Marcell Jansen hitting the winner.